PageSigner works with many Chromium-based browsers (e.g. Chromium, Vivaldi, Brave, Google Chrome) You can load PageSigner from the source files of this repo this way: 1. go to chrome://extensions and Enable "Developer mode" 2. Click "Load unpacked" 3. Navigate inside pagesigner's top folder and click Open. ----- Firefox addon creation is not supported anymore due to missing API in Firefox.