So why single out Chrome in this repository and post? Feels like a hit piece on Chrome this way.

Well, I didn't really consider Firefox and I didn't want to publish anything unsubstantiated about it. No intent to single out or attack Chrome - I've changed the title to clarify that now that I have evidence this works in FF.

Investigating and reporting a bug should never be considered "singling out" of a piece of software. Personally, I'd be grateful if someone pointed out a critical issue like this in my code. It means I have the opportunity to fix it!

Well, Chrome is a very commonly used browser, and I would guess that other browsers look to it for guidance on features.

Also, it seems to me that the post is only a proof of concept. "Hey, look at what happens here in this browser. I've extensively proven that it's possible. Maybe people should check it out under other circumstances."