[raszi]

Compare the branch with origin/main by default. A local main can be old, and then the tool also lists the files that changed on main.

• Use origin/main if changed.defaultBranch is not set. --base still overrides it.
• Stop reading init.defaultBranch. That setting only names the first branch of a new repository.
• Fail with an error if origin/main does not exist. New scenarios test this case and an old local main.
• Remove the README part about changed.defaultBranch origin/main, because it is the default now.
• Add a Motivation section, an Alternatives section, and more examples to the README.