• #12533 remapped the rule RUF025 as C420.

• #15104 added a different new rule under the code RUF025.

The immediate issue is that even though RUF025 has just appeared in documentation, if you enable it, the rule doesn't actually work, and you just get the following warning:

warning: `RUF025` has been remapped to `C420`.

So I suppose (luckily?) the new rule was not actually added yet because it's impossible to use it, it only appears in docs and in the codebase.

Rule codes that were remapped from are supposed to remain reserved forever, right?