435
iFixit wants to fix the soldering iron
(www.engadget.com)
This is a most excellent place for technology news and articles.
I believe this is one of those Google "F it I am going to make this protocol my own way without anyone else's input" which results in security concerns and also Mozilla prioritizes it being a browser more.
Searching serial looks like this is still the case. There are security and privacy concerns over it.
https://mozilla.github.io/standards-positions/
For those not wanting go search:
Mozilla's Position
Devices that offer serial interfaces often expose powerful, low-level functions over the interface with little or no authentication. Exposing that sort of capability to the web without adequate safeguards presents a significant threat to those devices. A user deliberately installing a site-specific add-on may be adequate, given sufficiently understandable consent copy.
Seems reasonable to me.