You could modify the git bundle to not set the scope for modified files, but I think
you're better of customizing the theme so that those colors do play nice.
I want the scope to be there, I just don't want TextMate to draw anything for that
scope that is not set in the theme.
To change the theme you open the bundle editor,
(Bundles -> Edit Bundles...), select the bundle containing the theme you're using
and select the theme under "Themes". Now search for "markup.changed",
there you can set the foreground and background color.
Tried that of course. I had no background for markup.changed at all. If I set some it gets
painted over the predefined background.
It's easy to see this if you set the color to #00000088. You'll see that now you
get a dimmed yellow, not just half-transparent black.
I want to remove the background totally. Having just the colored text looks nicer and
cleaner to me.
I could use the color of the window background here for "markup.changed" to
overlay the yellow if I wasn't using the half-transparent color there.