Hi @nj2
The one https://author-myserver.adobeaemcloud.com/ui#/aem/aem/start.html with # is Unified Shell which aligns the “shell” look and feel of Adobe Experience Cloud applications and services. It’s a single-page application that delivers user experience in a single instance and AEM as a Cloud Service (Author Service) is integrated with Unified Shell to improve the user experience and unify it with all the other Experience Cloud applications.
More details here:-
https://experienceleague.adobe.com/docs/experience-manager-cloud-service/content/overview/aem-cloud-...
It is enabled out of the box but You can disable it as well if you plan to do some customization:-
https://experienceleague.adobe.com/docs/experience-manager-cloud-service/content/overview/aem-cloud-...
And the other one https://author-myserver.adobeaemcloud.com/aem/start.html without # is the regular one.
Hope this helps!
Regards,
Nitesh
