How to custmoize git.el's diff face in Emacs?

Question

My Emacs is set to display text as black background on green text. The problem is when i do a diff using git.el the part at the top of the buffer showing changes starting with --- or +++ is showed using greenish color on green so i can't read i check git.el but can not seem to figure out which face is used to control this ?

Answer 1

Go to the buffer, move point to the mystery face and type C-u C-x = (aka C-u M-x what-cursor-position). Emacs first tells you a lot about the character at point, but then also notes:

There are text properties here:
  face                 diff-header
  fontified            t

So the face you are looking for is diff-header.