[ztjio]

For quite some time you could do this manually without much trouble, but you did need to know a few obscure steps to do it right. Basically a matter of finding the ID of the game so you can copy a certain metadata file along with the actual game data.

I used the trick to copy some games to my Steam Deck back in the Fall. I speculated then that they might make this a genuine feature since it's so simple. I'm glad to see it happened.

[earthling8118]

Steam has had a dedicated feature for this for a decade now. Except it didn't do it over the network, just files which you had to provide transport for yourself

[ztjio]

This is different than the backup feature, behaves extremely differently. The backup feature is so insanely slow that restoring from a typical USB media a 120GB game takes longer than downloading that same game on 100mbps internet connection.

This method I'm referring to (and probably what they will codify) is much, much faster.