I haven't messed with Firefox's PWA feature/taskbar-tabs[1] but it seems like under the hood it's just using shortcuts so you're probably looking for -taskbar-t

I haven't messed with Firefox's PWA feature/taskbar-tabs[1] but it seems like under the hood it's just using shortcuts so you're probably looking for -taskbar-tab This redditor looks like he's doing close to what you're asking with the caveat of needing an entry in taskbartabs.json to use -taskbar-tab (and maybe Windows OS only) [2] I don't think it's completely chromeless but you can probably hide everything via custom CSS: ctrl+shift+i (dev tools) -> f1 (settings) check advanced settings: enable browser chrome and add-on debugging enable remote debugging ctrl+shift+alt+i (browser dev tools) Find element IDs or class names and try out CSS rules to your heart's content. Set toolkit.legacyUserProfileCustomizations.stylesheets = true and put your changes in Firefox/Profiles/$profilename/chrome/userChrome.css. Remember to turn off the advanced settings when you're done. [1] https://firefox-source-docs.mozilla.org/browser/components/taskbartabs/docs/index.html https://firefox-source-docs.mozilla.org/browser/components/t... [2] https://www.reddit.com/r/firefox/comments/1ljidwp/progressive_web_apps_taskbar_tabs_are_now_kind_of/n1quidy/ https://www.reddit.com/r/firefox/comments/1ljidwp/progressiv...