I’ve been working on WebHID implementation for Servo for some time. I was able to create a proof of concept and you can send reports to HID devices now. I shared my progress on Servo Zulip but TSC of Servo was unsure about adding this spec to the Servo as it is still in draft stage and there are some security concerns.
So the suggestion was to write it as an external dependency through an API that enables any kind of spec to be added to Servo externally. Now, I’ll try implement the spec with this approach.