@Punti I have never seen this error before. Doing a little search engine foo I came across this topic where they talk about an issue in the GnuTLS libraries used by git and that the whole issue was magically fixed (by Github?) in the end: https://discourse.pi-hole.net/t/error-git-remote-https-died-of-signal-4/56558/17
Though on the other hand this is really strange because I did give it a try in my Ubuntu 20.04 test machine and it does not run into the same problem. Maybe this really is a temporary Github problem??