To add the latest release mirror to your Spack (recommended):
$> spack mirror add E4S https://cache.e4s.io/23.11
$> spack buildcache keys -it
Or, add the combined cache to your Spack:
$> spack mirror add E4S https://cache.e4s.io
$> spack buildcache keys -it
111,843 total packages
Last updated 2023-11-09 15:48 PST