People in this thread (and the author of the article) are under the assumption that Mozilla is running this PPA, it's run by the community.

That being said ricotz has been participating in the Ubuntu community for a very long time, and from a practical standpoint you'll probably be ok.

There's a good reason for Ubuntu to push people away from PPAs as distribution methods for end users and instead use them for what they were original supposed to be used for, make it easy for distro developers to fire up repos for testing/development with the intent of that work making it back into distro and Debian. Snaps have lots of problems but using the distro-staging PPA isn't a good idea either.