A colleague analyzed Firefox' behavior at the point of crash and realized that it happened during stack probing. The JIT touched the area that would hold the variables for the next JavaScript call and somehow hit an overflow.
https://bugzilla.mozilla.org/show_bug.cgi?id=1839139#c8
This is where things got weird, Google's code was allocating 20000 variables in a single frame. Ouch, that's probably some machine-generated code which went out of hand. Think twice before using ChatGPT to write code. 3/6