Solved problem with integration #guix with [matrix] room.

Topic of #guix:
Savannah servers under attack: try and try again...

Didn't know it few days ago when tried to install guix on Arch Linux.
I'd used mirror on GitHub in url parameter of guix pull:
https://github.com/guix-mirror/guix

Is it official mirror?
(Didn't meet mention of it on Guix site)