Steam used to have a way of backing up installs yourself; if it’s still a thing, I have no idea where it’s hidden now.

Library -> Game context menu -> Manage -> Back up game files…

The game files are just directories you can archive however you want anyway. No stinky ‘installer executables’ necessary. (:

It is a variable holding the process id of the shell instance interpreting the command. You could say “yourself” instead.