But - if you're ready to accept an app that's in beta and if you're happy to mess around with changing your phone's 'region' in Settings for the installation (and change it back afterwards) and you're OK with a client that's 100MB (yes, really) then knock yourself out, Facebook (Beta) UWP is in the Store here.
Here's the new UWP in action. No doubt it will gradually get released across platform variants and regions in due course, in time for the Windows 10 Anniversary Update:
It's in public beta at last - Facebook's own Windows 10 (UWP) client!
The layout is clear and clean, if utterly AMOLED-unfriendly. Ah well. Also, it's just.... Facebook. I still maintain that many people will be just as happy with the web site(!)
This client follows neatly on from last week's similar availability of the Facebook Messenger client - which this application err... calls. So they had to release these apps in the right order!
Browsing through my notifications...
A comprehensive set of Settings, though almost identical to those in the mobile web view. Again, do we REALLY need a client for Facebook?