うーむこれすごいな。ange-ftp のノリで、しかし ssh とか (rsh とか telnet とか sudo とか…) 任意のプロトコルの上でfind-file なり dired なりできるというフレームワーク

TRAMP stands for `Transparent Remote (file) Access, Multiple Protocol'. This
package provides remote file editing, similar to ange-ftp and EFS.

The other difference is that ange-ftp uses FTP to transfer files between the
local and the remote host, whereas TRAMP uses a combination of rsh and rcp or
other work-alike programs, such as ssh/scp. A emacs elisp tool to edit files
on remote host using telnet, rsh, scp, ssh and more.

いまこの文章も、tramp で ssh/scp 経由で find-file とか Dired とか使いまくりでかいてます。

やや、auto-save がちょっとせつないかなこれ。