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.
parameters.url = file.url;
    }
    
    const apiParameters = AppOptions.getAll(OptionKind.API);
    for (const key in apiParameters) {
      let value = apiParameters[key];
      if (key === "docBaseUrl" && !value) {
        if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("PRODUCTION")) {
          value = document.URL.split("#")[0];
        } else if (PDFJSDev.test("MOZCENTRAL || CHROME")) {
          value = this.baseUrl;
        }
      }
      parameters[key] = value;
    }
    
    if (args) {
      for (const key in args) {
        parameters[key] = args[key];
      }
    }
    const loadingTask = getDocument(parameters);
    this.pdfLoadingTask = loadingTask;
    loadingTask.onPassword = (updateCallback, reason) => {
      this.pdfLinkService.externalLinkEnabled = false;
      this.passwordPrompt.setUpdateCallback(updateCallback, reason);
      this.passwordPrompt.open();
    };
    loadingTask.onProgress = ({ loaded, total }) => {
      this.progress(loaded / total);