Update:
The page is back and it seems Astoria is still alive!! TBC..
Microsoft’s Project Astoria allows developer to port Android apps to Windows 10 Mobile and it was aim to solve the much criticized Windows Phone app gap problem.
However last month Android subsystem gone missing from Windows 10 Mobile build 10549 and porting of Android apps were no longer working for Windows Mobile users. One school of thought regarding why Microsoft may have removed Astoria was that Build 10536.1004 suffered gradual degradation in performance over time and we know that happens with Android. No preview build after Build 105349 had Astoria on-board and that is the case with RTM Build 10586 too.
Now it seems Microsoft has given up on Project Astoria, as Windows Bridge for Android home page is no longer available. This is a clear signal that Microsoft will focus on Project IslandWood for porting iOS apps rather than Android apps. It also seem many Microsoft employees who were earlier working on Astoria Project have updated their profiles to reflect that they have been moved to other projects.