From 74a8907b50a033857d3d96024d07d6509f26c576 Mon Sep 17 00:00:00 2001
From: Anatolii Khmarskii <a.khmarskii@adguard.com>
Date: Wed, 20 May 2026 14:38:19 +0300
Subject: [PATCH] AG-43745 Add urltransform supported version for
 browser-extension and mv3 limitations

---
 docs/general/ad-filtering/create-own-filters.md | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/docs/general/ad-filtering/create-own-filters.md b/docs/general/ad-filtering/create-own-filters.md
index d4c225ad5b4..5b4a2bfe4a2 100644
--- a/docs/general/ad-filtering/create-own-filters.md
+++ b/docs/general/ad-filtering/create-own-filters.md
@@ -1425,7 +1425,7 @@ These modifiers are able to completely change the behavior of basic rules.
 | [$removeheader](#removeheader-modifier) | ✅ | ✅ [*[7]](#removeheader-modifier-limitations) | ✅ [*[7]](#removeheader-modifier-limitations) | ✅ [*[7]](#removeheader-modifier-limitations) | ❌ | ❌ | ❌ |
 | [$removeparam](#removeparam-modifier) | ✅ | ✅ | ✅ [*[6]](#removeparam-modifier-limitations) | ✅ | ❌ | ❌ | ❌ |
 | [$replace](#replace-modifier) | ✅ | ❌ | ❌ | ✅ | ❌ | ❌ | ❌ |
-| [$urltransform](#urltransform-modifier) | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ |
+| [$urltransform](#urltransform-modifier) | ✅ | ✅ | ✅ [*[8]](#urltransform-modifier-limitations) | ✅ | ❌ | ❌ | ❌ |
 | [$reason](#reason-modifier) | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ |
 | [noop](#noop-modifier) | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ❌ |
 | [$empty 👎](#empty-modifier "deprecated") | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ |
@@ -2953,7 +2953,7 @@ AdGuard products that use a [CoreLibs] version older than 1.20 only support a si
 
 :::info Compatibility
 
-This section only applies to AdGuard for Windows, AdGuard for Mac, AdGuard for Android, and AdGuard for Linux with [CoreLibs] v1.17 or later.
+This section only applies to AdGuard for Windows, AdGuard for Mac, AdGuard for Android, and AdGuard for Linux with [CoreLibs] v1.17 or later, and to [AdGuard Browser Extension][ext-chr] v5.5 or later.
 
 :::
 
@@ -3042,6 +3042,19 @@ Rules with the `$urltransform` modifier are supported by AdGuard for Windows, Ad
 
 `$urltransform` rules with [content-type modifiers](#content-type-modifiers) are supported starting from [CoreLibs] v1.19 or later. In earlier versions, content-type modifiers were not allowed with `$urltransform`.
 
+Rules with the `$urltransform` modifier and [content-type modifiers](#content-type-modifiers) are also supported by [AdGuard Browser Extension][ext-chr] v5.5 or later, and by [AdGuard for Chrome MV3][ext-mv3] with [limitations](#urltransform-modifier-limitations).
+
+:::
+
+##### `$urltransform` modifier limitations {#urltransform-modifier-limitations}
+
+:::caution Limitations
+
+In [AdGuard for Chrome MV3][ext-mv3], the `$urltransform` modifier has the following limitations:
+
+1. **No decode stages** — pipeline transforms containing `b64` (Base64 decode) or `pct` (percent-decode) stages are not supported and will be discarded.
+2. **No global replacement** — only the **first match** is replaced. The `/g` (global) flag is ignored. This is usually not an issue for full-URL transforms anchored with `^`, but path-only patterns that rely on replacing all occurrences will only replace the first one.
+3. **Single redirect per request** — when multiple `$urltransform` rules match the same request, only the highest-priority one takes effect. In CoreLibs, all matching rules are applied sequentially.
 :::
 
 #### **`$reason`** {#reason-modifier}