$ git clone -n https://github.com/xcp-ng-rpms/kernel-alt /var/lib/mock/v8.3-incoming-6006-11270/root/chroot_tmpdir/scmroot/kernel-alt
Cloning into '/var/lib/mock/v8.3-incoming-6006-11270/root/chroot_tmpdir/scmroot/kernel-alt'...
$ git reset --hard 421619a1110d93f2f43d0d71ecde11e6b353b264
Downloading SOURCES/kernel-4.19.19.tar.gz (161 MB)
HEAD is now at 421619a Use updategroup.py from /opt/xensource/bin