On the March 7th I participated in Guix Patch Review Session:
libreplanet.org/wiki/Group:Gui

Thanks to Romain Garbage (gitlab.inria.fr/rgarbage) who helped me with "git send-email" I'm now figured out how to use this command properly to send patches for GNU Guix. My first patch that was sent this way:
debbugs.gnu.org/cgi/bugreport.

Before I used to send my patches as attachments to plain emails I wrote in Emacs GNUS.