One of the most common conflicts, especially in backports, is this file: https://github.com/10gen/mongo/blob/master/etc/backports_required_for_multiversion_tests.yml
Because everyone just adds entires to the end of it.

Can we do something about it?

Idea 1: make it a directory where each file is a small yaml?

Idea 2: Sort the entries. Then everyone isn't fighting over that next last line. I'd even put a meaty comment at the end of each section saying "you probably don't want to put it at the end, please keep it alphabetized based on file name!" (or something to that effect).
One big churn that causes conflicts, but then it's smooth(er) sailing from then on.