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