I don't have a good source at hand, but there was even a preview version of Windows 10 Mobile available that had support built in. You could get it from the insider program. Now that the whole ecosystem gets wound down it becomes incredibly frustrating trying to revisit those old systems. You can easily recreate installs of Windows 98 or XP in various flavors and patch levels, but for Windows Phone this has become mostly impossible.

For example, the store for WP8.1 and older has shut down, so you can no longer get the app for upgrading to 10. There was a tool released by the end of 2019 that can do it via USB, but that stopped working in October since the server it contacts now requires TLSv1.2, and the tool was written in .NET 4 which doesn't do 1.2 by default. So there is a registry hack you can use to enable it again, until eventually that doesn't work anymore either. There are inofficial, incomomplete mirrors of some device specific factory images, and the pretty awsome "windows phone internals" tool for rooting and modding some devices, which was mostly a one man show.

With said tool and a lot of patience, it should still be able to get one of the two insider builds of win10mobile running that had android emulation, given you find the instructions, all the files and images required. And then it's still only an alpha version that emulates the Android 4.4 API.

I have a friend whos working on software archival, so through him I became aware of the importance of trying to preserve these kind of things, and those very closed and additionally niche platforms are the second hardest thing to preserve, after cloud services.

It's called Project Astoria if you want to look it up.

It's been a good while since I read the original story, but Wikipedia [0] has some background and should have some citations if you want to dig in further

[0] https://en.m.wikipedia.org/wiki/Windows_Subsystem_for_Linux