These components were built as part of the Servo project and then ported to Firefox, so you'd probably just want to ask the Servo team directly. You can find th

These components were built as part of the Servo project and then ported to Firefox, so you'd probably just want to ask the Servo team directly. You can find them on IRC, in the channel #servo on irc.mozilla.org. There is https://blog.servo.org/ https://blog.servo.org/, but it's mostly gradual updates on things, not a general overview.