**These files are for use by the test suites only!** They are secrets
that have been checked into version control, and therefore can _no
longer be trusted as secrets_. Ideally, these files will eventually be
replaced by a test harness that runs

    ssh-keygen -t rsa -b 4096 -m PEM -f jwtRS256.key # Don't add passphrase
    openssl rsa -in jwtRS256.key -pubout -outform PEM -out jwtRS256.key.pub

then munges the generated files and adds them to a `.env`.