Backports of foreign patches?

[Harald Anlauf]

Dear all,

just a hypothetical question: assume that some patch for a regression was
applied only to e.g. master some time ago but might be worth a backport,
the regression was indicated in the PR, and the patch author does not answer
any related queries in the PR?

How could/should/would one proceed?

Would it be acceptable to backport the patch after a sufficient waiting time
(at least e.g. one or two months)?  With a notification to the ML?  Or does
it require an additional OK from a reviewer?

Or would one pass an invisible red line?

Thanks,
Harald