Based on our 700+ articles, we will release a fresh, accurate site compatibility dataset that covers the status of the obsolete features on each Firefox channel including Nightly, Beta/DevEdition and ESR. The data will be available in Q4 2018 in the portable JSON format.
Obviously, we are not aiming at creating comprehensive browser support tables that can be seen on MDN, Can I use or QuirksMode, but with the per-channel deprecation details, we hope both Firefox developers and web developers will find our own dataset useful.
An extension for Visual Studio Code is also planned.
The checker may utilize part of external compatibility data to deal with unsupported features as well as other browsers, and also enhance the functionality with some utilities like regression alerts and reporter.