>50% of words? Characters? LoC? Files?

Yeah, this is the bit where it really falls down, regardless of how you define "mostly"!

To me majority != mostly.

I agree that they have different connotations. However, in the absence of other information, I don't see how we could ever collectively agree on a better value. The least subjective option, as far as I'm concerned, is "more than 50%". If a is 50.001 and b is 49.999, then a is the one with the most, not b.

It's reasonable not to assume what they meant. They have a clear stance on the subject instead of letting us guess

How would anyone ever be able to arbitrate this? It's an unenforceable policy if you actually care about fairness.

I suspect rather than posting whataboutisms that it would be more useful to adhere to the spirit of the rule rather than asking how close you can get to violating it without actually getting kicked off.

This is so obviously the case that I'm having a seriously hard time assuming good faith from everyone arguing about the edge cases.

“Did you really think we want those laws observed?" said Dr. Ferris. "We want them to be broken." -Atlas Shrugged