How do I know if a repository is official?

Question

linux

How to find out if a program has an official repository for linux, and vice versa, if there is a repository of any program on the Internet, is it official, and not some kind of "left" one?
Take for example Viber or Telegram

Answer 1

1 if the software is in the boxed repository that comes with the OS, then most likely there is an official version, possibly with some edits for compatibility, but definitely not a left one.
2 further we are already looking for software developers on the off site, for example, things like zabbix or percona have their own repositories, although in many distributions their software is in the main repositories (often lags behind in versions)
3 if there are no repositories or ready-made packages on the off site of developers , but there is a link to the sorts or github, then we already google the left repositories, etc., and there can be anything, if you are afraid - collect the software yourself from the sorts from the developers' site, if you need a large-scale deployment - make your own rpm or deb package.

Answer 2

just google, go to their website and look there.
or go to the repositories, look there. not the fact that it will be written in plain text.
usually the official one is more hyped.