You cannot do the same with Snap and that’s by design. Canonical wants to be the sole gatekeeper of Linux software
Then why did they publish source code and documentation for all parts of it, so you can create your own snap store?
You can; the issue is that you can’t add two snap repositories at once.
This is functionally pretty much the same thing, as nobody is likely to want to use snap while locking themselves out of the main snap repository, but it’s still important to make the distinction.
In theory I guess there’s nothing stopping you setting up a mirror of the main snap repo with automatic package scraping, but nobody’s really bothered exploring it seeing as no distro other than Ubuntu has taken any interest in running snap.
I know that it’s possible to change the one entry but adding additional ones is not possible and that’s by design.
From reading this that’s not the whole story. Someone working at canonical successfully made a version of snap that could use alternative stores, but the default version does not allow it
And honestly at the point of installing that modified version you may as well just install a different package manager anyway
