> Firefox doesn't resize small enough to fit on the screen.

What exactly does this mean?

* I can make the FF desktop window super tiny

* I can do browser zooming down to 30%

* even if the chrome would obscure the webpage viewport I can go into fullscreen mode

* FF itself has a responsive design mode and ships with Iphone and other small form factors in the dropdown

I understand that it may be easier to tweak Gnome's browser for adding navigation gestures/url bar appearance, etc. But I can't imagine how FF wouldn't be able to display a web page in a way that fits the Librem 5 screen.

Can I ask what you mean by that? Firefox's core has been used on the mobile phone in multiple applications that function just fine and Firefox's desktop version is perfectly capable of resizing down to mobile phone sizes, even emulating a phone if you want.

Does that mean no extensions and thus no ad blocker? If so, do they have another ad block solution at the device level?