UnfoldControl by Derage

Mobile layouts often look stretched on the big inner screen of a foldable phone, with huge images that fill the whole screen. Firefox has a Desktop site switch, but you have to flip it by hand every time you open or close the phone.

UnfoldControl does that for you. On the open inside screen, pages are drawn at a width you choose, 1280 pixels by default, so sites show their normal desktop layout. Fold the phone, or hold the inside screen in portrait, and sites keep their own layout.

On for every site by default, with one switch to turn it off.

One render width, from 640 to 3840 pixels. 1280 is the usual desktop width.

Per-site choice: When wide, Always, or Site size.

Optional: use that same width on the inside screen in portrait, or on the cover screen in landscape.

A short setup measures the phone and sets the switchover for you.

Keeps the layout when you reload a page.

Works alongside content blockers such as uBlock Origin.

Why it needs access to all websites

To draw the wider layout, UnfoldControl changes the page viewport as the page loads and asks the site for its desktop version. It only does this when the window is wide enough, and only on sites where it is switched on.

Privacy

UnfoldControl collects no data. Settings stay on your device, and nothing is sent anywhere.

Made for the Galaxy Z Fold, and it should work on any foldable. It also installs on desktop Firefox, where pages stay as they are.