Build 17092 will have an upper limit of 50. I hope that no one wants to open 51, 100 or 200 repositories.

In the preferences you now can search for options. We won't duplicate this logic in the Ctrl+P command.

Commits by committer name: how would this help if you find hundreds of results?

Is still something open for this request?

Works for me in 21.1.

When exactly this default should be applied? When creating the repository?

Will be implemented in build 17088.

To what exact command line parameters of 'git clean' your options correspond?

The changelog.txt is only updated for an official preview release, not for each intermediate build. In the preferences, hosting providers section you can find Azure DevOps.