As this third and final tweet gets pushed out, this will mark 10 years since the original compile of this build in 2014, as the string "140912-1613" means September 12, 2014, at 16:13 military time (which is 4:13 PM). (3/3)
That build was 9841. It combined visual features of the Windows 8.1 start screen and the old Windows 7 start menu into one. Some people still didn't like the tiles, but this was a move towards making the OS a lot more user-friendly. (2/3)
It has been a tradition for me to commemorate this day (September 12) every year since 2019.
Windows 10 (known as Threshold at the time) was in its Tech Preview phase, and this is known to be the first public build that got released to consumers, known as Tech Preview. (1/3)