I'm having MitM, and some stupid websites like Hacker News which have managed to install an HSTS policy prior to MitM can no longer be accessed from SeaMonkey/Firefox.
Without HSTS being installed, there's always an option to proceed anyways, but with HSTS, there's no more of any such option (so much for the browser being a User-Agent!).
How do I make my Firefox / SeaMonkey User-Agent to ignore either all HSTS or the individual ones, or uninstall all/some of them, or any other way to access a site that has stopped working, without indiscriminately deleting all history/data of any such site?