I think it applies to all error codes, but let me give an example where I encountered that.

Consider:

data = do_some_transformations()
return data

Which is a violation of RET504 - unnecessary assignment.

I needed to perform the assignment and return data, not return do_some_transformations(), so added a noqa: RET504 with explanation of why I want to bypass the rule:

data = do_some_transformations()
return data  # noqa: RET504 - to be able to debug the returned object.

Then I disabled RET504 in ruff config completely, and this noqa became unused. Here is where RUF100 comes into play, as it complains on unused error codes, and provides a fix.

The fix was:

-    return data  # noqa: RET504 - to be able to debug the returned object
+    return data  # - to be able to debug the returned object

While I believe it should have been:

-    return data  # noqa: RET504 - to be able to debug the returned object
+    return data

As it's probably quite safe to assume that entire content of the comment noqa is part of is explaining why a rule should by bypassed.

• List of keywords you searched for before creating this issue: RUF100
• Most similar open issue: RUF100 for noqa: E501 not at end of line #7851
• A minimal code snippet that reproduces the bug: see above.
• The command you invoked: ruff check --fix
• The current Ruff version: 0.5.1.