If you're a fan of the Facebook app on Windows 10, you're in for some bad news. The app is no longer available, as spotted by Aggiornamenti Lumia. It's not searchable in the Microsoft Store, and if you've got a direct link to the listing, it shows that the app is unavailable.
That's about all that we know. The change could be temporary with a new version on the way, although it does seem likely that the app would be removed completely while waiting for an update. Still, Facebook doesn't seem to be abandoning Windows 10 completely, since Messenger and Instagram are both still available. In fact, Instagram was just added to the Store as a PWA.
Presumably, the app will continue to work for the foreseeable future, as long as you already have it. For the best experience, you'll want to use the browser though. That's what most people do anyway, as is evident by Facebook's decision to remove the app.
We've reached out to both Facebook and Microsoft for comment, so if we hear anything, we'll let you know.
Update: Both Microsoft and Facebook have responded to requests for statements. Representatives from both companies said, "As of February 28, the Facebook desktop app for Windows is no longer available. People can still easily access and enjoy all of the features of Facebook via desktop browser." Additionally, a Facebook representative confirmed that there are no plans for a new Windows 10 app, and that neither Messenger nor Instagram are being removed.