Github has been petitioned, begged and implored to enable SSL on custom domains running on Github pages. It looks like they are finally and quietly delivering SSL support with LetsEncrypt certificates being deployed.
Please be aware that it hasn’t been officially released, this is why I have migrated two small Jekyll sites and not this blog, for example. YMMV.
https://www.dblock.org to fix asset and other internal links.
I couldn’t figure out how to make those relative to either HTTP or HTTPs.
_head.html from HTTP to HTTPs.
I couldn’t find a plugin that could make a 301 redirect before page load, something that Google recommends.