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.
this.pdfRenderingQueue.printing = !!this.printService;
    this.pdfRenderingQueue.isThumbnailViewEnabled =
      this.pdfSidebar.visibleView === SidebarView.THUMBS;
    this.pdfRenderingQueue.renderHighestPriority();
  },
  beforePrint() {
    
    
    this.pdfScriptingManager.dispatchWillPrint();
    if (this.printService) {
      
      
      
      return;
    }
    if (!this.supportsPrinting) {
      this.l10n.get("printing_not_supported").then(msg => {
        this._otherError(msg);
      });
      return;
    }