$ git clone -n https://src.fedoraproject.org/rpms/R-rtracklayer.git /var/lib/mock/f38-build-724173-99404/root/chroot_tmpdir/scmroot/R-rtracklayer
Cloning into '/var/lib/mock/f38-build-724173-99404/root/chroot_tmpdir/scmroot/R-rtracklayer'...
$ git fetch origin 201537901551b2ec6ff4dba27e4c634eb80ea997:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-rtracklayer
 * [new ref]         201537901551b2ec6ff4dba27e4c634eb80ea997 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2015379 R-maint-sig mass rebuild