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 (
      info.IsXFAPresent &&
      !info.IsAcroFormPresent &&
      
      !pdfDocument.isPureXfa
    ) {
      console.warn("Warning: XFA is not enabled");
      this.fallback(UNSUPPORTED_FEATURES.forms);
    } else if (
      (info.IsAcroFormPresent || info.IsXFAPresent) &&
      !this.pdfViewer.renderInteractiveForms
    ) {
      console.warn("Warning: Interactive form support is not enabled");
      this.fallback(UNSUPPORTED_FEATURES.forms);
    }
    if (info.IsSignaturesPresent) {
      console.warn("Warning: Digital signatures validation is not supported");
      this.fallback(UNSUPPORTED_FEATURES.signatures);
    }
    
    let versionId = "other";
    if (KNOWN_VERSIONS.includes(info.PDFFormatVersion)) {
      versionId = `v${info.PDFFormatVersion.replace(".", "_")}`;
    }
    let generatorId = "other";
    if (info.Producer) {
      const producer = info.Producer.toLowerCase();
      KNOWN_GENERATORS.some(function (generator) {
        if (!producer.includes(generator)) {
          return false;