But they are zip files. (Though `file somebook.epub tells me "data". Sigh. Desktop and OS seem to be on different pages.)

Just like .css and .log are text files, but I may not want the same default file handler.

What I like is having *.epub open in, say, calibre, but if I append a .zip extension then it will open in xarchive.

Anyways, I open most things from the command line and wrote my version of 'open' so I get what i expect 99% of the time. :)

I'm using KDE3 so I'm not expecting any upstream fixes for this in my lifetime. I can live with crafting my own solutions.

What might work best is if mime types were used by default but forcing behavior for specific extensions was much easier. Get the best of both worlds (which I can mostly do in KDE3 Konqueror but it's tedious.)

File(1) on my Debian wheezy says they're epubs. File has dealt with nested formats for decades. It examines up to the first 1024 bytes of the file IIRC.

Other examples: tar.gz, WAR files, most ODF formats.

Edit: smartphone tyops fixed.

... and file(1) under my Ubuntu 11.10 system calls 'em zips.

Debian added upstream epub support (and backed out its own) in September, 2011, so this is a pretty recent feature.