[anarcat]

wow. I used ftp for years and even ran my own server for a while and never knew that was a thing. is that something that was actually used to mirror those sites? Debian mirrors certainly don't use this (anymore?) at least, for example..

[fletchowns]

It's called FXP: https://en.wikipedia.org/wiki/File_eXchange_Protocol

FlashFXP was a popular client that supported this: https://en.wikipedia.org/wiki/FlashFXP

[xorcist]

It's called fxp and you can still find information on it. In the top site scene it was widely used.