It looks like this extension is defined in /usr/share/mime/packages/freedesktop.org.xml, which dpkg -S says is part of the shared-mime-info package. It's still there in oneiric too [1].
[1] http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/oneiric/shared- mime-info/oneiric/view/head:/freedesktop.org.xml ** Package changed: mime-support (Ubuntu) => shared-mime-info (Ubuntu) ** Changed in: shared-mime-info (Ubuntu) Status: New => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/611763 Title: markdown files ending in .md get marked as 'application/x-genesis-rom' To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/shared-mime-info/+bug/611763/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs