if (cookieService != null) {
           cookieService.setCookieString(cookieUri, null, "CertCheckDone=1;", null);
           myTrace("cookie is " + cookieService.getCookieString(cookieUri, null));
       }
   }

After moving to Firefox 78 ESR, get/setCookieString() is no longer working. For example: if (cookieService != null) { cookieService.setCookieString(cookieUri, null, "CertCheckDone=1;", null); myTrace("cookie is " + cookieService.getCookieString(cookieUri, null)); } } Firefox is running in kiosk mode and this code was executed with a hook in browser.js. Can someone please help me with this? Are there APIs I can use in place of these or are the Webextension APIs the only way to set a cookie now? I have tried playing around and can load a temporary extension but it's removed when restarting the browser and this also has to run in kiosk mode.