What does mean by ↓ and C besides file name in Xcode9 Project Navigator?

Question

I know about M, A, U, ?, R, I.

I searched for the ↓ and C but not found any helpful resources.

This p

Answer 1

C means conflict — you tried to merge (or implicitly merge due to a pull) a branch where, in the marked file, git can't automatically resolve the differences between your working copy and the other branch. You'll need to use Xcode's version editor or an external tool to manually decide which changes from each side to keep, then tell git that the conflicts are resolved (IIRC in Xcode you can do this by right-clicking on the file in the navigator).

↓ means your working copy is "behind" the other branch by some number of commits (in this case, because the conflict meant it couldn't catch up).