Re: customizing `frame-background-mode'

[Richard M. Stallman]

    Wouldn't it be better to use the same syntax for members of
    all supported archivers (gzip, zip, tar)?

gzip is not an archiver, it is a compression program.

    Currently `buffer-file-name' of the visited archive member
    uses three different syntaxes:

    "/home/handa/temp.po.gz"

That is not a special convention, it is the file name.

    "/home/handa/temp.zip:vi.po"
    "/home/handa/temp.tar!vi.po"

Changing the zip case to use ! instead of : is ok with me.