I made Facebook and FB Messenger for Windows. It was considered a complete failure by management as it never got above 1% of the usage by windows users vs the website.
If you're allowed to say, are you referring to the Windows 10 ports of the iOS apps that were done via Osmeta in 2016, or the earlier WinRT-native version? If the former, that was a non-starter for me and my blind friends due to deep accessibility issues, probably having to do with the Osmeta port/reimplementation of UIKit. Edit to add: And we wanted something that was easier to use with a Windows screen reader than the desktop website, particularly for Facebook proper.
To be honest, the Microsoft store was the biggest single impediment to success the project ever had. All of the ridiculous UWP requirements or exceptions and friction to install doomed it, start menu tile be damned.
And the start menu tile BS wasn't impactful except for the narrowly avoided multibillion dollar GDPR fine Facebook almost fell headfirst into when they declared "mission accomplished" and I realized they forgot the apps existed and escalated, just before the deadline.
I deserved a bonus for finding that, yet it didn't even register on my PSC.
