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.
if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
      throw new Error("Not implemented: unbindWindowEvents");
    }
    const { _boundEvents } = this;
    window.removeEventListener("visibilitychange", webViewerVisibilityChange);
    window.removeEventListener("wheel", webViewerWheel, { passive: false });
    window.removeEventListener("touchstart", webViewerTouchStart, {
      passive: false,
    });
    window.removeEventListener("click", webViewerClick);
    window.removeEventListener("keydown", webViewerKeyDown);
    window.removeEventListener("resize", _boundEvents.windowResize);
    window.removeEventListener("hashchange", _boundEvents.windowHashChange);
    window.removeEventListener("beforeprint", _boundEvents.windowBeforePrint);
    window.removeEventListener("afterprint", _boundEvents.windowAfterPrint);
    window.removeEventListener(
      "updatefromsandbox",
      _boundEvents.windowUpdateFromSandbox
    );
    _boundEvents.windowResize = null;
    _boundEvents.windowHashChange = null;
    _boundEvents.windowBeforePrint = null;
    _boundEvents.windowAfterPrint = null;
    _boundEvents.windowUpdateFromSandbox = null;
  },
  accumulateWheelTicks(ticks) {