• -s (--tls) Generate a self-signed certificate, and enable TLS. The cert
  bundle is stored in ~/.devd.cert
• Add the X-Forwarded-Host header to reverse proxied traffic.
• Disable upstream cert validation for reverse proxied traffic. This makes
  using self-signed certs for development easy. Devd shoudn't be used in
  contexts where this might pose a security risk.
• Bugfix: make CSS livereload work in Firefox
• Bugfix: make sure the Host header and SNI host matches for reverse proxied
  traffic.