Re: treat .xpi as archive file

[Richard Stallman]

    > But wouldn't it be better instead of these extension to add ZIP magic
    > string "PK^C^D" to `magic-mode-alist' to recognize archive files for
    > any possible extension?

    Yes, in principle (like compressed files), but please don't mess with
    that now.

I tend to agree it is better to recognize these by filenames.  That is
because there is a very strong convention to use those filenames for
these files.  People won't, and shouldn't, expect Emacs to treat
something as a ZIP file if it doesn't have the right file name.