I haven't ever seen periods at the end of the type, only when there's a comment too. Can you clarify where else in core follows this pattern?

Hey, @danielbachhuber !

Periods at the end of the type are the part of standard WordPress PHP documentation in the Core handbook. You can check this information here https://make.wordpress.org/core/handbook/best-practices/inline-documentation-standards/php/#1-functions-class-methods

I read:

@return: Should contain all possible return types, and a description for each. Use a period at the end. Note: @return void should not be used outside of the default bundled themes.

This @return doc doesn't have a description, so I don't think it needs a period.

@danielbachhuber Though it does mention Use a period at the end.
What do you think about that? Let me know. I'll follow your lead.

Only add a period if there's actually a description, please. Better yet, add descriptions where they're missing, and then you can add a period to that :)

@danielbachhuber Got it, re-submitting the corrected version.