What made Microsoft open-source exFAT in 2019?

[Ertio]

In 2019, Microsoft officially released the exFAT specifications. Before then, everything known about it was only known from reverse engineering, mainly by the heroes at the SANS institute.

 

Did Microsoft do it from the goodness of their hearts or was there some motive behind it?     

 

Why it matters: exFAT is the pre-loaded file system on exFAT memory cards and pretty much all SD XC cameras and camcorders use it. Portable external hard drives and SSDs use it too. Only exFAT is fully read-and-write supported all three of Windows, Mac, and Linux. It the common denominator for storing any files beyond the debilitating 4 GB.