Progressive code QA in general is IMO an underexplored space. Thankfully linters have now largely given way to opinionated formatters (xfmt, black, clang-format) but in the olden days I wished there was a way to check in a parallel exemptions file that could be periodically revised downward but would otherwise function as a line in the sand to at least prevent new violations from passing the check.

I'd be interested in similar capabilities for higher-level tools like static analyzers and so on. The point is not to carry violations long term, but to be able to burn down the violations over time in parallel to new development work.