What do the circles' color in gource mean?

Question

When we launch gource in software version control (e.g. in local git repository) while generating video of project evolution, the circles change their color. I suppose they indicate some state. But what state exactly do they indicate of?

Answer 1

I think it indicates the file type, not a state...

If the parameter "--key" is used, a brief list of type/color is showed in the screen.

Documentation from Gource