Jenkins stack-os-matrix runs are giving this error:
CondaHTTPError: HTTP 500 INTERNAL SERVER ERROR for url <http://conda-mirror.lsst.codes/pkgs/free/linux-64/repodata.json>
Reevaluate conda mirror, cleanup jenkins jobs
Russ Allbery reports that this is an Amazon S3 bucket, so it's not clear why it should be returning 500s.
We no longer use the conda mirror