outputs that there could be up to 1011 affected packages.

The scripts checks for a url-fetch uri of the form
"github.com/.*/archive/", which seems to be the one used for the
dynamically generated archives.

Here are the first 10 lines of the output:
--8<---------------cut here---------------start------------->8---
Number of potentially problematic GitHub packages:1011
fdupes
cbatticon
sedsed
cpulimit
autojump
sudo
thermald
progress
dstat
[...]
--8<---------------cut here---------------end--------------->8---

I've checked the first few with for example:
--8<---------------cut here---------------start------------->8---
guix build --source --no-substitutes sedsed
--8<---------------cut here---------------end--------------->8---

and they were OK though.

Maxim