https://experienceleague.adobe.com/en/docs/target-dev/developer/client-side/at-js-implementation/functions-overview/registerextension-atjs-1x
How Do I Use the registerExtension() Function? | Adobe Target
Use the registerExtension() function for the Adobe Target at.js JavaScript library to register a specific extension. (at.js 1.x)
how do iusefunctionadobetarget