I just now stumbled upon this small problem, and I thought I might as well share it.
I’m currently using Fennec F-Droid 82.1.3 (Firefox built from its sources the F-Droid way) on /e/ Android 10 (Fairphone 3) and /e/ Android 9 (Fairphone 2), but I suspect the problem to be somewhat generic.
"Add to Home screen" or “Install”:
When setting up your home screen, you may want to have shortcuts to websites on it. No problem, Firefox will let you do that via three-dot-menu - “Add to Home screen”.
Unless … the website in question has been prepared to work as a PWA (Progressive Web App), in which case Firefox will only offer to “Install” it instead.
Major differences (as far as I can tell):
“Add to Home screen” will simply put a shortcut to the exact address you’re visiting at the moment to the home screen.
“Install” will put a shortcut to the home screen, which will launch the website as a PWA. There will be no browser UI elements, and the site will be launched with its index page, e.g. you can “Install” https://forum.fairphone.com/latest, but the PWA shortcut will only launch https://forum.fairphone.com.
What if you don’t want to have a PWA shortcut?
A PWA makes great sense for e.g. the Google Maps website … you don’t need the App and you still get an App-like experience and convenience out of this.
But the limitation to the index page of a website and the missing browser UI are not what you want to have when you just want to open a page in the browser and be able to open links in new browser tabs and all that, this is not possible with a PWA.
Problem is … you don’t get a choice. Firefox 82 (as of now) just switches “Add to Home screen” and “Install” based on the capabilities of the website. Private mode makes no difference.
It takes a moment to load a page, and at first Firefox doesn’t know the capabilities of the website it processes.
Once a page starts to load, the three-dot-menu will already offer “Add to Home screen”, until Firefox has determined it can switch the menu entry to “Install”.
During this time you can “force” Firefox to give you a simple page shortcut instead of a PWA.