accidentally discovered a way to read Facebook direct messages on the mobile site, at least on an Android phone with Chrome browser.
first, enable desktop mode: click on the 3 vertical buttons on the upper right, scroll down to "Desktop site", and click. this will make everything shrink to unreadability, but be patient. turn your phone sideways, that will help, then click the messages icon, it looks something like "(~)". now hit the "back" button in your browser. if you're lucky, as I was, your browser is still sending a "desktop" User-Agent string to Facebook, but for some reason it's using the CSS for a mobile device, so everything is readable, and it doesn't redirect you to Google Play to install the messenger app.
now when you switch to another site, you may find it's still in desktop mode, even if while in Facebook you clicked the 3 dots again you might have found it's disabled. at that point you can disable it.
last updated 2019-10-12 23:40:02. served from tektonic.jcomeau.com