Glad to see you, August!
Apparently, the mention of "FIDOnet.CLUB" is turned into a hot-link in Telegram, and that takes us to a website. I guess the invite link is available there.
You are on the main page of the site dedicated to the FIDOnet Club camp, which gathers at the All-Russian Day of the System Administrator.
In July 2016, it was decided to register the camp, develop its logo, banner, after which the camp met for the first time at DSA-2016.
A distinctive feature of the camp (which is clear from the name) is that all its members are somehow connected to the Fido network.
https://brorabbit.g0x.ru/pic/61ba389f.jpg
*** [Netmail-to-Telegram address: 474405162@2:460/256]
... Tag, you are IT!
--- tg BBS v0.7.1
* Origin: Fido by Telegram BBS from Stas Mishchenkov (2:460/256)