nice, thanks!
i previously had a barebones version using fetchTree documented as an alternative to nix run, and now opened a PR to mention nix-run as well.
(nitpick: i kinda like tree references’ terser syntax better than https://github.com/nixos/nixpkgs/archive/refs/heads/master.tar.gz 
, while they also seem able to handle the remote fetches.)
ideally tho, i hope we could get a command like this built-in, so libraries would feel more comfortable documenting remote invocation using it.