How do I disable the colored highlighting left of the line numbers in the Bracket Editor? What is it called/for?

See below for a screenshot of my brackets editor in a css file. I see the colored highlighting for all file types. I am not sure what to call it. I have been downloading extensions lately so it could be one of them but not sure what its called and thus can't search online for how to disable it.

Solution

Those colored marks are the "gutter marks" from the Brackets Git extension. They indicate added (green), modified (yellow/orange), or deleted (red) lines in the current file.

Personally, I find them very helpful. In case you still want to turn them off, go to the Git Settings and check the box for "Use Git gutter marks".