Because this page includes a <platinum-https-redirect> element, it will
automatically redirect to the https: version of this page when the following is
true:
http: protocol.localhost
or one of its equivalents.
In order to test this functionality, you can visit this page via
http://polymerelements.github.io/platinum-https-redirect/demo/index.html.
Because that URL uses http: and is not on localhost, it will
automatically redirect to
https://polymerelements.github.io/platinum-https-redirect/demo/index.html
instead.