Something else such docs could cover is how to manage remote Hg repos such that the "Create Patch" button does the right thing.

Basically, you need to make sure an appropriate CPython version is found in the ancestors of the tip your working branch. This is most easily achieved either by working directly on the default branch in your remote repo, or else by merging directly from default to your feature branch (i.e. not via another feature branch).

If you don't follow this rule, the generated patch will occasionally incorrectly revert changes in CPython that you didn't intend to affect.

(see http://psf.upfronthosting.co.za/roundup/meta/issue428 for some background)