$ git clone -n https://github.com/fedora-riscv/clang.git /var/lib/mock/f40-build-2707343-71313/root/chroot_tmpdir/scmroot/clang
Cloning into '/var/lib/mock/f40-build-2707343-71313/root/chroot_tmpdir/scmroot/clang'...
$ git fetch origin 6b45c6ebfe8fd2ed77b8b4365c24b045f0f8b8e1:KOJI_FETCH_HEAD
From https://github.com/fedora-riscv/clang
 * [new ref]         6b45c6ebfe8fd2ed77b8b4365c24b045f0f8b8e1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6b45c6e Add support for riscv64