Recently updated Ubuntu 23.10:
I tried it several times - the same result.
$ git clone https://github.com/dfinity/motoko
Cloning into 'motoko'...
remote: Enumerating objects: 104759, done.
remote: Counting objects: 100% (5702/5702), done.
remote: Compressing objects: 100% (2333/2333), done.
error: RPC failed; curl 92 HTTP/2 stream 5 was not closed cleanly:
CANCEL (err 8)
error: 1600 bytes of body are still expected
fetch-pack: unexpected disconnect while reading sideband packet
fatal: early EOF
fatal: fetch-pack: invalid index-pack output
