[RFC] Branch naming -- allowed characters?

I just noticed this while trying to track quilt project and making a
local branch with name '.pc':

    'fatal: '.pc' is not a valid branch name.'

Would it be possible to allow using arbitrary names with branches in
future git, even UTF-8?

If that is not possible, would it be possible to at least broaden the
charcter set with regular typeable US ascii letters, excluding the
control ones. Something found in filenames/URLs. Like regexp:

    [][{}()_=+%!&@#~*.:;,/A-Za-z-]

Jari

[*] Emacs even saves with names like: *Messages*