$ git clone -n https://src.fedoraproject.org/rpms/rust-libgit2-sys0.15.git /var/lib/mock/f38-build-side-43-rust-devel-1416642-31457/root/chroot_tmpdir/scmroot/rust-libgit2-sys0.15
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1416642-31457/root/chroot_tmpdir/scmroot/rust-libgit2-sys0.15'...
$ git fetch origin eecc843cc654f0d239442740e654e1721a680fe4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-libgit2-sys0.15
 * [new ref]         eecc843cc654f0d239442740e654e1721a680fe4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eecc843 Initial import (libgit2-sys 0.15 compat package)