Hi there! Welcome to the Salt Community! Thank you for making your first contribution. We have a lengthy process for issues and PRs. Someone from the Core Team will follow up as soon as possible. In the meantime, here’s some information that may help as you continue your Salt journey.
Please be sure to review our Code of Conduct. Also, check out some of our community resources including:

• Salt’s Contributor Guide
• Join our Community Discord
• Salt Project YouTube channel
• Community Wiki

There are lots of ways to get involved in our community. Every month, there are around a dozen opportunities to meet with other contributors and the Salt Core team and collaborate in real time. The best way to keep track is by subscribing to the Salt Community Events Calendar.
If you have additional questions, email us at saltproject.pdl@broadcom.com. We’re glad you’ve joined our community and look forward to doing awesome things with you!

Where are we testing that max_depth is being honored?

I modified the test in tests/pytests/functional/states/file/test_directory.py::test_directory_max_depth to also modify and check files. If you cherry-pick only this change to tests into mainline, the test will fail. Previously, we only checked if folders are modified and this behaviour is correct, only files were handled incorrectly.

Additionally, if this bug exists in 3006.x, the PR should be created against the 3006.x branch. Master is for new features.

This bug exists in Salt ever likely (can't verify) since 6d52aeb, and it was reported in the linked issue to be at earliest in 2019.2.0 . Should I re-target to 3006.x or something even older? Or, should I create a new PR?

3006.x is the earliest supported branch. That's where it should go.

Created #68256 to merge into 3006.x . I'm not used to GitHub, so I'm sorry if I should have done it other way.

OK, we'll close this one in favor of #68256