Since lots of our source files contain vim magical comments (at the top
or bottom), I reckon vim is more common in our community than emacs (-*-
coding: ... -*- being an "emacs cookie").

Python looks for something like "coding[:=]\s*([-\w.]+)" (pep 0263, see
http://www.python.org/dev/peps/pep-0263/; 'coding', a ':' or '=',
optional whitespace, and the encoding spec.).

Vim looks for 'enc=' or 'encoding='; the latter works for Python, too.
The emacs cookie is not recognised by vim (by default).