I was able to run a basic command and get a response --
{
"id": "1",
"method": "Browser.getVersion"
}
{
"id": "1",
"result": {
"protocolVersion": "1.3",
"product": "Firefox",
"revision": "1",
"userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0",
"jsVersion": "1.8.5"
}
}
Now just need to figure out which commands are supported by Firefox. FWIW, it doesn't appear to recognize Page.addScriptToEvaluateOnNewDocument as a valid method.