Following the conventions of the "h" project [1], the client's asset
server (localhost:3001) and demo page server (localhost:3000) will be
served over SSL if a certificate (".tlscert.pem") and private key
(".tlskey.pem") are found in the root of the repository.

This can be useful for testing the development client on pages served
over SSL without having to disable mixed content warnings in the
browser.

[1] https://h.readthedocs.io/en/latest/developing/ssl/