Try modifying a webpage’s source to open with <html mozdisallowselectionprint>. If that works, you can make that universal using any page-mod plugin (though not

Try modifying a webpage’s source to open with <html mozdisallowselectionprint>. If that works, you can make that universal using any page-mod plugin (though not necessarily the userstyle CSS-only ones). I’m mobile-only tonight so I can’t test myself, but derived from: https://searchfox.org/firefox-main/source/layout/printing/nsPrintJob.cpp#268 https://searchfox.org/firefox-main/source/layout/printing/ns...