diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 21e6386f1..199e918bf 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -37998,6 +37998,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -38032,7 +38033,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/serviceworker.generated.d.ts b/baselines/serviceworker.generated.d.ts
index 098ada31a..8756c6330 100644
--- a/baselines/serviceworker.generated.d.ts
+++ b/baselines/serviceworker.generated.d.ts
@@ -9856,6 +9856,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -9890,7 +9891,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/sharedworker.generated.d.ts b/baselines/sharedworker.generated.d.ts
index 591d59bba..85b245e57 100644
--- a/baselines/sharedworker.generated.d.ts
+++ b/baselines/sharedworker.generated.d.ts
@@ -9393,6 +9393,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -9427,7 +9428,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.5/dom.generated.d.ts b/baselines/ts5.5/dom.generated.d.ts
index 84e2025b4..6dc459faf 100644
--- a/baselines/ts5.5/dom.generated.d.ts
+++ b/baselines/ts5.5/dom.generated.d.ts
@@ -37972,6 +37972,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -38006,7 +38007,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.5/serviceworker.generated.d.ts b/baselines/ts5.5/serviceworker.generated.d.ts
index 8542ee79c..43f458007 100644
--- a/baselines/ts5.5/serviceworker.generated.d.ts
+++ b/baselines/ts5.5/serviceworker.generated.d.ts
@@ -9853,6 +9853,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -9887,7 +9888,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.5/sharedworker.generated.d.ts b/baselines/ts5.5/sharedworker.generated.d.ts
index 66c2a41f2..de1d79421 100644
--- a/baselines/ts5.5/sharedworker.generated.d.ts
+++ b/baselines/ts5.5/sharedworker.generated.d.ts
@@ -9390,6 +9390,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -9424,7 +9425,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.5/webworker.generated.d.ts b/baselines/ts5.5/webworker.generated.d.ts
index ed90d652f..367f580fa 100644
--- a/baselines/ts5.5/webworker.generated.d.ts
+++ b/baselines/ts5.5/webworker.generated.d.ts
@@ -11297,6 +11297,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -11331,7 +11332,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.6/dom.generated.d.ts b/baselines/ts5.6/dom.generated.d.ts
index 0a39ce8da..25ca7cde7 100644
--- a/baselines/ts5.6/dom.generated.d.ts
+++ b/baselines/ts5.6/dom.generated.d.ts
@@ -37995,6 +37995,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -38029,7 +38030,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.6/serviceworker.generated.d.ts b/baselines/ts5.6/serviceworker.generated.d.ts
index 8542ee79c..43f458007 100644
--- a/baselines/ts5.6/serviceworker.generated.d.ts
+++ b/baselines/ts5.6/serviceworker.generated.d.ts
@@ -9853,6 +9853,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -9887,7 +9888,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.6/sharedworker.generated.d.ts b/baselines/ts5.6/sharedworker.generated.d.ts
index 66c2a41f2..de1d79421 100644
--- a/baselines/ts5.6/sharedworker.generated.d.ts
+++ b/baselines/ts5.6/sharedworker.generated.d.ts
@@ -9390,6 +9390,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -9424,7 +9425,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.6/webworker.generated.d.ts b/baselines/ts5.6/webworker.generated.d.ts
index ed90d652f..367f580fa 100644
--- a/baselines/ts5.6/webworker.generated.d.ts
+++ b/baselines/ts5.6/webworker.generated.d.ts
@@ -11297,6 +11297,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -11331,7 +11332,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.9/dom.generated.d.ts b/baselines/ts5.9/dom.generated.d.ts
index 216f42f49..fcc76b917 100644
--- a/baselines/ts5.9/dom.generated.d.ts
+++ b/baselines/ts5.9/dom.generated.d.ts
@@ -37995,6 +37995,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -38029,7 +38030,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.9/serviceworker.generated.d.ts b/baselines/ts5.9/serviceworker.generated.d.ts
index a1386ceb8..146bc5c30 100644
--- a/baselines/ts5.9/serviceworker.generated.d.ts
+++ b/baselines/ts5.9/serviceworker.generated.d.ts
@@ -9853,6 +9853,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -9887,7 +9888,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.9/sharedworker.generated.d.ts b/baselines/ts5.9/sharedworker.generated.d.ts
index 73d2b16eb..9cd35e2e3 100644
--- a/baselines/ts5.9/sharedworker.generated.d.ts
+++ b/baselines/ts5.9/sharedworker.generated.d.ts
@@ -9390,6 +9390,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -9424,7 +9425,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/ts5.9/webworker.generated.d.ts b/baselines/ts5.9/webworker.generated.d.ts
index 57880b22b..748293f29 100644
--- a/baselines/ts5.9/webworker.generated.d.ts
+++ b/baselines/ts5.9/webworker.generated.d.ts
@@ -11297,6 +11297,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -11331,7 +11332,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/baselines/webworker.generated.d.ts b/baselines/webworker.generated.d.ts
index 5c2851ac1..9c8715c36 100644
--- a/baselines/webworker.generated.d.ts
+++ b/baselines/webworker.generated.d.ts
@@ -11300,6 +11300,7 @@ interface WebGLRenderingContextBase {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getError) */
     getError(): GLenum;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getExtension) */
+    getExtension(name: string): any;
     getExtension(extensionName: "ANGLE_instanced_arrays"): ANGLE_instanced_arrays | null;
     getExtension(extensionName: "EXT_blend_minmax"): EXT_blend_minmax | null;
     getExtension(extensionName: "EXT_color_buffer_float"): EXT_color_buffer_float | null;
@@ -11334,7 +11335,6 @@ interface WebGLRenderingContextBase {
     getExtension(extensionName: "WEBGL_draw_buffers"): WEBGL_draw_buffers | null;
     getExtension(extensionName: "WEBGL_lose_context"): WEBGL_lose_context | null;
     getExtension(extensionName: "WEBGL_multi_draw"): WEBGL_multi_draw | null;
-    getExtension(name: string): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getFramebufferAttachmentParameter) */
     getFramebufferAttachmentParameter(target: GLenum, attachment: GLenum, pname: GLenum): any;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/WebGLRenderingContext/getParameter) */
diff --git a/inputfiles/overridingTypes.jsonc b/inputfiles/overridingTypes.jsonc
index da25af03d..725751894 100644
--- a/inputfiles/overridingTypes.jsonc
+++ b/inputfiles/overridingTypes.jsonc
@@ -33,45 +33,6 @@
             "WebGLRenderingContextBase": {
                 "methods": {
                     "method": {
-                        "getExtension": {
-                            "name": "getExtension",
-                            "additionalSignatures": [
-                                "getExtension(extensionName: \"ANGLE_instanced_arrays\"): ANGLE_instanced_arrays | null",
-                                "getExtension(extensionName: \"EXT_blend_minmax\"): EXT_blend_minmax | null",
-                                "getExtension(extensionName: \"EXT_color_buffer_float\"): EXT_color_buffer_float | null",
-                                "getExtension(extensionName: \"EXT_color_buffer_half_float\"): EXT_color_buffer_half_float | null",
-                                "getExtension(extensionName: \"EXT_float_blend\"): EXT_float_blend | null",
-                                "getExtension(extensionName: \"EXT_frag_depth\"): EXT_frag_depth | null",
-                                "getExtension(extensionName: \"EXT_sRGB\"): EXT_sRGB | null",
-                                "getExtension(extensionName: \"EXT_shader_texture_lod\"): EXT_shader_texture_lod | null",
-                                "getExtension(extensionName: \"EXT_texture_compression_bptc\"): EXT_texture_compression_bptc | null",
-                                "getExtension(extensionName: \"EXT_texture_compression_rgtc\"): EXT_texture_compression_rgtc | null",
-                                "getExtension(extensionName: \"EXT_texture_filter_anisotropic\"): EXT_texture_filter_anisotropic | null",
-                                "getExtension(extensionName: \"KHR_parallel_shader_compile\"): KHR_parallel_shader_compile | null",
-                                "getExtension(extensionName: \"OES_element_index_uint\"): OES_element_index_uint | null",
-                                "getExtension(extensionName: \"OES_fbo_render_mipmap\"): OES_fbo_render_mipmap | null",
-                                "getExtension(extensionName: \"OES_standard_derivatives\"): OES_standard_derivatives | null",
-                                "getExtension(extensionName: \"OES_texture_float\"): OES_texture_float | null",
-                                "getExtension(extensionName: \"OES_texture_float_linear\"): OES_texture_float_linear | null",
-                                "getExtension(extensionName: \"OES_texture_half_float\"): OES_texture_half_float | null",
-                                "getExtension(extensionName: \"OES_texture_half_float_linear\"): OES_texture_half_float_linear | null",
-                                "getExtension(extensionName: \"OES_vertex_array_object\"): OES_vertex_array_object | null",
-                                "getExtension(extensionName: \"OVR_multiview2\"): OVR_multiview2 | null",
-                                "getExtension(extensionName: \"WEBGL_color_buffer_float\"): WEBGL_color_buffer_float | null",
-                                "getExtension(extensionName: \"WEBGL_compressed_texture_astc\"): WEBGL_compressed_texture_astc | null",
-                                "getExtension(extensionName: \"WEBGL_compressed_texture_etc\"): WEBGL_compressed_texture_etc | null",
-                                "getExtension(extensionName: \"WEBGL_compressed_texture_etc1\"): WEBGL_compressed_texture_etc1 | null",
-                                "getExtension(extensionName: \"WEBGL_compressed_texture_pvrtc\"): WEBGL_compressed_texture_pvrtc | null",
-                                "getExtension(extensionName: \"WEBGL_compressed_texture_s3tc\"): WEBGL_compressed_texture_s3tc | null",
-                                "getExtension(extensionName: \"WEBGL_compressed_texture_s3tc_srgb\"): WEBGL_compressed_texture_s3tc_srgb | null",
-                                "getExtension(extensionName: \"WEBGL_debug_renderer_info\"): WEBGL_debug_renderer_info | null",
-                                "getExtension(extensionName: \"WEBGL_debug_shaders\"): WEBGL_debug_shaders | null",
-                                "getExtension(extensionName: \"WEBGL_depth_texture\"): WEBGL_depth_texture | null",
-                                "getExtension(extensionName: \"WEBGL_draw_buffers\"): WEBGL_draw_buffers | null",
-                                "getExtension(extensionName: \"WEBGL_lose_context\"): WEBGL_lose_context | null",
-                                "getExtension(extensionName: \"WEBGL_multi_draw\"): WEBGL_multi_draw | null"
-                            ]
-                        },
                         "pixelStorei": {
                             "name": "pixelStorei",
                             "signature": {
diff --git a/inputfiles/patches/webgl.kdl b/inputfiles/patches/webgl.kdl
index efb9fed9f..3d314d954 100644
--- a/inputfiles/patches/webgl.kdl
+++ b/inputfiles/patches/webgl.kdl
@@ -1,3 +1,173 @@
 interface-mixin WebGLRenderingContextBase {
   property canvas exposed=Window
+
+  method getExtension {
+    param extensionName overrideType="\"ANGLE_instanced_arrays\""
+    type ANGLE_instanced_arrays nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_blend_minmax\""
+    type EXT_blend_minmax nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_color_buffer_float\""
+    type EXT_color_buffer_float nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_color_buffer_half_float\""
+    type EXT_color_buffer_half_float nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_float_blend\""
+    type EXT_float_blend nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_frag_depth\""
+    type EXT_frag_depth nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_sRGB\""
+    type EXT_sRGB nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_shader_texture_lod\""
+    type EXT_shader_texture_lod nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_texture_compression_bptc\""
+    type EXT_texture_compression_bptc nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_texture_compression_rgtc\""
+    type EXT_texture_compression_rgtc nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"EXT_texture_filter_anisotropic\""
+    type EXT_texture_filter_anisotropic nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"KHR_parallel_shader_compile\""
+    type KHR_parallel_shader_compile nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"OES_element_index_uint\""
+    type OES_element_index_uint nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"OES_fbo_render_mipmap\""
+    type OES_fbo_render_mipmap nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"OES_standard_derivatives\""
+    type OES_standard_derivatives nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"OES_texture_float\""
+    type OES_texture_float nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"OES_texture_float_linear\""
+    type OES_texture_float_linear nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"OES_texture_half_float\""
+    type OES_texture_half_float nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"OES_texture_half_float_linear\""
+    type OES_texture_half_float_linear nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"OES_vertex_array_object\""
+    type OES_vertex_array_object nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"OVR_multiview2\""
+    type OVR_multiview2 nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_color_buffer_float\""
+    type WEBGL_color_buffer_float nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_compressed_texture_astc\""
+    type WEBGL_compressed_texture_astc nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_compressed_texture_etc\""
+    type WEBGL_compressed_texture_etc nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_compressed_texture_etc1\""
+    type WEBGL_compressed_texture_etc1 nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_compressed_texture_pvrtc\""
+    type WEBGL_compressed_texture_pvrtc nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_compressed_texture_s3tc\""
+    type WEBGL_compressed_texture_s3tc nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_compressed_texture_s3tc_srgb\""
+    type WEBGL_compressed_texture_s3tc_srgb nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_debug_renderer_info\""
+    type WEBGL_debug_renderer_info nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_debug_shaders\""
+    type WEBGL_debug_shaders nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_depth_texture\""
+    type WEBGL_depth_texture nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_draw_buffers\""
+    type WEBGL_draw_buffers nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_lose_context\""
+    type WEBGL_lose_context nullable=#true
+  }
+
+  method getExtension {
+    param extensionName overrideType="\"WEBGL_multi_draw\""
+    type WEBGL_multi_draw nullable=#true
+  }
 }
diff --git a/src/build/patches.ts b/src/build/patches.ts
index 2c78a4290..7c949ebce 100644
--- a/src/build/patches.ts
+++ b/src/build/patches.ts
@@ -7,6 +7,7 @@ import type {
   WebIdl,
   Method,
   Typed,
+  Param,
   Dictionary,
   Member,
   Signature,
@@ -261,7 +262,7 @@ function handleMethod(child: Node): DeepPartial<OverridableMethod> {
   const name = string(child.values[0]);
 
   let typeNode: Node | undefined;
-  const params: { name: string; type: string }[] = [];
+  const params: Partial<Param>[] = [];
 
   for (const c of child.children) {
     switch (c.name) {
@@ -275,7 +276,12 @@ function handleMethod(child: Node): DeepPartial<OverridableMethod> {
       case "param":
         params.push({
           name: string(c.values[0]),
-          type: string(c.properties.type),
+          ...optionalMember("type", "string", c.properties?.type),
+          ...optionalMember(
+            "overrideType",
+            "string",
+            c.properties?.overrideType,
+          ),
         });
         break;
 
diff --git a/unittests/files/webgl.ts b/unittests/files/webgl.ts
new file mode 100644
index 000000000..4de348526
--- /dev/null
+++ b/unittests/files/webgl.ts
@@ -0,0 +1,8 @@
+function assertType<T>(_x: T) {}
+
+const canvas = document.getElementById("canvas") as HTMLCanvasElement;
+const gl = canvas.getContext("webgl")!;
+
+const ext_ANGLE_instanced_arrays = gl.getExtension("ANGLE_instanced_arrays");
+// TypeScript should infer: ANGLE_instanced_arrays | null
+assertType<ANGLE_instanced_arrays | null>(ext_ANGLE_instanced_arrays);