I'm getting this in Firefox while in Chrome the same works
Error: Type error for parameter filter (Error processing urls.0: Expected string instead of undefined) for webRequest.onBeforeSendHeaders.
import browser from "webextension-polyfill";
browser.webRequest.onBeforeSendHeaders.addListener(
listener,
{
urls: [url],
},
["requestHeaders", "blocking", "extraHeaders"]
);
I verified the url is a string, any idea where this is from?