I was wondering if WebGL is considered stable enough to be enabled by default. It makes some PDFs render much faster and it has been off by default for a while now, so we have had quite some time to test it.

If we decide to enable WebGL by default, we should not forget to update https://github.com/mozilla/pdf.js/blob/master/extensions/chromium/preferences_schema.json#L39 as well.

/cc @yurydelendik 
/cc @Snuffleupagus (because IIRC you were testing WebGL too)

if (!AppOptions.get("pdfBugEnabled")) {
      return undefined;
    }
    const hash = document.location.hash.substring(1);
    if (!hash) {
      return undefined;
    }
    const hashParams = parseQueryString(hash),
      waitOn = [];
    if ("disableworker" in hashParams && hashParams.disableworker === "true") {
      waitOn.push(loadFakeWorker());
    }
    if ("disablerange" in hashParams) {
      AppOptions.set("disableRange", hashParams.disablerange === "true");
    }
    if ("disablestream" in hashParams) {
      AppOptions.set("disableStream", hashParams.disablestream === "true");
    }
    if ("disableautofetch" in hashParams) {
      AppOptions.set(
        "disableAutoFetch",
        hashParams.disableautofetch === "true"
      );
    }
    if ("disablefontface" in hashParams) {
      AppOptions.set("disableFontFace", hashParams.disablefontface === "true");