> In the future issues should be sent to the bug tracker. Issues can be
 > opened by emailing ~scoopta/wofi@todo.sr.ht if you don't have a sr.ht
 > account.

Sorry about that!

 > That being said I don't run nix and have no experience with it
 > however I've asked people I know who run nix about this and they are
 > unable to reproduce it. It's entirely possible this is something 
that's
 > nix specific and should be posted to the corresponding bug tracker.
 > Especially seeing as all your errors are from fontconfig, wofi is a 
GTK
 > app, and I do no manual font handling.

It think it had something to do with the unstable channel. Now it is 
working both in unstable and in NixOS 20.09, so the bug must have been 
fixed.

Jorge Blázquez Saborido