If the existing implementation is perfectly good, writing your own is either pride, stupidity, or a learning exercise.

I would take for granted that the Firefox developers aren't stupid, and that they have enough interesting work to do that they aren't going to spend time on it as a learning exercise.

Ah, okay. That feels a hyperbolic to be pride or stupidity, rather than just a poor analysis of the efficacy of an existing solution. Thank you for your response.