...mainly due to arbitrarily failing ci builds, as this doesn't appear
to affect local builds/nix builds on remote builders, just fresh builds
in the ci.
the explanation for why this is happening might be that certain package
VCS's don't allow many/frequent connections from IP ranges other than
GOPROXY's (Google's).
that is sheer speculation, though.
however, it is still true that there are "no" failed ci builds with
GOPROXY env var set to its default value (left untouched), which does
indeed indicate that the above mentioned might be the root cause of the
issue after all.
surtur