Thanks for the response! I'm sorry if I muddied the waters. Here's the straightforward maybe a slightly clearer version of what I'm after:

1. I want a way to ignore the baseline for a specified set of files

For example, I'm working on a legacy file in Domain/Value/Foo.php and I would like to fix any baselined issues while I'm already touching that file. It would be great to be able to apply this logic to all the files I've touched in my branch (git diff --name-only --diff-filter=ACMRTUXB develop..HEAD).

2. I want a way to run a heightened level of analysis for a specified set of files

For example, if my whole legacy project is baselined at Level 4 but I want the work I'm doing in my branch to be held to a higher standard, I want to run phpstan analyse --level 6 but only see the results for files I've changed.

Both of these are achievable in userland, e.g. without changing PHPStan itelf.

I want a way to ignore the baseline for a specified set of files

Take for example https://github.com/shipmonk-rnd/phpstan-baseline-per-identifier. You can pre-process/post-process the baseline however you want. So it'd be easy for you to write some tooling about removing baselined entries for certain files.

I want a way to run a heightened level of analysis for a specified set of files

Increase the level to 6 and generate a baseline before you start working in your branch. That way you'll see all level 6 errors from your changes.

ignore the baseline for a specified set of files

I do this by hand now, but because the baseline entries are multiple lines it doesn't make it easy to script. I see the project you referenced has a Neon parser, which is an option but also a time commitment. If nobody else would find this feature helpful then I could pursue that.

heightened level of analysis for a specified set of files

What you described is what I am doing currently! But it's a multistage process, and since my work is with legacy code its one I repeat frequently and would love to be able to configure.