We could use:
https://github.com/mozilla/pdf.js/blob/c3d08580627471432a6ad0b2fdb948df64126afa/src/display/api.js#L929

and look at bit 4.

The following pdf:
https://orimi.com/pdf-test.pdf
is not editable in neither Acrobat nor Edge nor Foxit and nor Okular.
console.warn("Warning: XFA Foreground documents are not supported");
      } else {
        console.warn("Warning: XFA support is not enabled");
      }
      this.fallback(UNSUPPORTED_FEATURES.forms);
    } else if (
      (info.IsAcroFormPresent || info.IsXFAPresent) &&
      !this.pdfViewer.renderForms
    ) {
      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;
        }
        generatorId = generator.replace(/[ .-]/g, "_");
        return true;