Update: No, it is again a Windows 10 PC Build 15061 that has been released today, that after teasing on a smartphone.
Microsoft last pushed Build 15060 only to PC insiders in Fast Ring and skipped it for Mobile. But now it seems Windows 10 Mobile Build 15061 will be pushed to Fast Ring insiders today.
This has been teased by Dona Sarkar in a tweet today. If you notice hard you would be able to notice 15061 mentioned on the smartphone in the image.
There was once a #Ninjacat named Zac….
(I ran out of limerick-ey skills after that line)
— Dona Sarkar @ #MSIgnite (@donasarkar) March 17, 2017