The way I tend to explain it, the “community” repository is for just that: packages maintained by the community, by volunteers, because they want to, for the love of it. Not necessarily by the Manjaro team.
The vast majority of our packages come from Arch, and thus arent exactly maintained by Manjaro either.
Manjaro packages can be seen by the maintainer line of package information and seen at the gitlab.
If it isnt one of those packages, then its functioning the same way it does on Arch - simply put through our ‘curation’ or ‘Branch’ repository system.
(and then beyond that you of course have AUR or other 3rd party repos)