There are a few minor bug fixes in this release, but as Microsoft's Rich Turner notes, the bigger impact of WSL's new status is that developers will be able to report issues through Microsoft's usual support channels and expect them to be resolved.
"What will change is that you will gain the added advantage of being able to file issues on WSL and its Windows tooling via our normal support mechanisms if you want/need to follow a more formal issue resolution process. You can also provide feedback via Windows 10 Feedback Hub app, which delivers feedback directly to the team," wrote Turner.
Microsoft's Windows kernel team created WSL to enable native Linux ELF64 binaries to run on Windows. It emulates the Linux kernel and uses so-called 'pico processes' to direct Linux system calls to the Windows kernel.