Is there a point you're trying to make, or are you asking for technical information which would be better answered by man dpkg or a quick Internet search?
I am not trying to make any point, I am genuinely curious where dpkg is going to put those files since its the first time I read you can dot `dpkg --root=$HOME -i mypackage.deb`.
For instance I always do `python3 -m pip install --user wormhole` or `pip install --user wormhole` instead of sudoing my way to permissions hell. Python apps get installed in $HOME/.local/bin, so no cruft for other users.
But stuff installed with deb packages often have hard coded pathways and assumptions of where and how their files are run.
So I think it's fair to ask in reply to someone implying that `dpkg --root=$HOME -i mypackage.deb` is as clean/same as a flatpack behaviour "It installs only in my profile, so another user on the same machine doesn't have access. You can't do that with a .deb!"... It's fair to ask "where do those files in the deb package go ?" because if it works as implied (no pollution of the OS) I am certainly going to start testing installing things that way.
