Mercurial's color extension is great and all, but there isn't a list on that page of what the valid colors are. I looked for a python file named color, hoping I'd be able to read the source and see it there, but no luck. I was hoping to use grey or light grey for a color but it wasn't valid. Grey (or gray) seems like a pretty likely color to be in a list of colors.
Where can I find a list of valid colors for the color extension? Or where can I find the source for the color extension?
You can find the source code at Mercurial Color Extension.
By default, the colors it recognises are black, red, green, yellow, blue, magenta, cyan, white.
But, as you'll see from the source, it's possible to define custom colours, but how you do this will depend on your terminal. Search for brightblue in the source.