$ git clone -n https://src.fedoraproject.org/rpms/notmuch.git /var/lib/mock/f40-build-1325672-23538/root/chroot_tmpdir/scmroot/notmuch
Cloning into '/var/lib/mock/f40-build-1325672-23538/root/chroot_tmpdir/scmroot/notmuch'...
$ git fetch origin 4337b8ab776d02ce9ef9ecfcfed687e33047717a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/notmuch
 * [new ref]         4337b8ab776d02ce9ef9ecfcfed687e33047717a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4337b8a Emacs 29 has been pushed to F38, adjust