Created attachment 8899673 [details] Screenshot_20170821-204523.png User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:54.0) Gecko/20100101 Firefox/54.0 Build ID: 20170628075643 Steps to reproduce: Installed Firefox for Android (currently v55.0.2) and opened any website on my Nexus 5x. Actual results: Every web site opens the "desktop" site instead of "mobile" site, regardless of "request desktop site" setting. Expected results: Every web site defaults to the "mobile" site when available.
Hello, From your screenshot, I see you were referring to Facebook. I could not reproduce the issue on a Nexus 6 phone (Android 7.0), or other phones. But I could reproduce it on tablets: HTC Nexus 9 (Android 7.1.1) & Huawei MediaPad M2 (Android 5.1.1). The Facebook website behaves this way when you type in the URL, without the "m.", it does not redirect automatically to the mobile site. This also happens on Chrome and it's not a new behaviour on Firefox either. Does any other website you've used behave this way? For e.g. twitter.com?
The screenshot shows that Firefox is running with the tablet UI, which explains that part.
Iiinteresting. I do have my Nexus 5x display settings set to "Display: small" (the smallest option). After a reboot, I noticed that I was getting the mobile version of some sites; but after navigating to a few different ones I was getting desktop (or tablet) layouts again, even on sites where I was shown the mobile layout before. I'm at work right now, but I'll try to get some step-by-step reproductions for you guys later.
This will be caused by the different UA. You are using the tablet interface thus you get the tablet UA. Mozilla/5.0 (Android 4.4; Mobile; rv:41.0) Gecko/41.0 Firefox/41.0 Mozilla/5.0 (Android 4.4; Tablet; rv:41.0) Gecko/41.0 Firefox/41.0 https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/User-Agent/Firefox#Mobile_and_Tablet_indicators