$ git clone -n https://src.fedoraproject.org/rpms/rust-trybuild2.git /var/lib/mock/f40-build-2260685-54418/root/chroot_tmpdir/scmroot/rust-trybuild2
Cloning into '/var/lib/mock/f40-build-2260685-54418/root/chroot_tmpdir/scmroot/rust-trybuild2'...
$ git fetch origin 96494a2ecebca1b46d96e8cbdd04c3e56186e7fd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-trybuild2
 * [new ref]         96494a2ecebca1b46d96e8cbdd04c3e56186e7fd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 96494a2 Update to version 1.2.0; Fixes RHBZ#2253010