Ultimately we should not load about:plugins using the SystemPrincipal. Even though fine for now, we should address that problem in the upcoming future.

David, about:plugins is loaded in a content process using the SystemPrincipal. Can we just remove about:plugins since the GMPs listed in about:plugins are also listed in about:addons?

If so, could we redirect about:plugins to about:addons' Plugin section to retain backwards compatibility? That would not be a high priority.

Nika asked about removing the System principal in #ipc in December. The SystemPrincipal is not believed to be needed for about:plugins -- it was added due to localization limitations 18 years ago (see e.g. bug 56863 comment 63).

That said, about:plugins does seem to be pointless now. The closest thing to valuable info not in about:addons is the path to the file, and that is trivial to track down.

We could alias about:plugins to about:addons but I have my doubts that very many people even know about:plugins exists.