UIR Header Comments

 Huh... it looks like they fake-add the Strict-Transport-Security header <https://developer.mozilla.org/docs/Web/HTTP/Headers/Strict-Transport-Security> to every page you tell it to apply to, effectively making the browser do all the work in attempting to access a secure page. That's a clever way to accomplish it... UIR Header tells the website to give the browser the HTTPS version. Enforce Encryption tells the browser to try to load the HTTPS version, as though it came from the website. The Upgrade-Insecure-Requests header wouldn't really come into play at all. I mean, it could, but it probably wouldn't. It would be a website-by-website thing whether or not they're redundant. They shouldn't interfere with each other, at least.

 Encrypted Web (or HTTPS Everywhere) uses a list of rules to determine if a website supports HTTPS and redirects your browser to the secure version of the page, if it exists. UIR Header tells the website you're visiting that you want the secure version and lets the site you're visiting choose how to respond.

 For an explanation of what Upgrade-Insecure-Requests does, check out <https://stackoverflow.com/questions/31950470/what-is-the-upgrade-insecure-requests-http-header>. For an example, try out this website. Without this Add-on, visiting <http://realityripple.com> will remain insecure in Pale Moon. If you enable this add-on, however, you'll automatically be redirected to <https://realityripple.com>. It's basically a method of telling websites you want the secure version, if possible.