Git Gutter background color different than normal background

[mcookly]

Is there any reason the gutter background color is a different shade than the normal background? For example:

I know this is a pretty easy fix without modifying the source code. I'm just questioning the design decision and whether it should be adjusted to match the normal background.

[reedes]

I don't recall the specific motivation, but likely it was to contrast the border of the code area.