What are GCC and GCC High tenants?
GCC (Government Community Cloud) and GCC High tenants are special types of Office 365 environments built to ensure safe handling and processing of data in compliance with the demands for US government institutions.
You can find more information on these types of tenants in these articles by Microsoft: Office 365 GCC and Office 365 GCC High and DoD.
Can you use ShortPoint on GCC and GCC High tenants?
Yes. ShortPoint SPFx for Office 365 can be used in GCC and GCC high tenants. You can install it like any other environment using this installation tutorial.
However, there will be small limitations on these types of tenants due to their security restrictions.
Are there ShortPoint features that are unsupported on GCC and GCC High tenants?
ShortPoint features that rely on Microsoft Graph integration are not supported on GCC and GCC High tenants. This includes
Shared Events, My Events, Group Events (Outlook) connections,
and the Teams Design Element.
These restrictions are there due to the inherently different security levels and authorization points that GCC and GCC High tenants have.
Can you use ShortPoint to design a SharePoint tab in Microsoft Teams for GCC and GCC High tenants?
Yes, you can use ShortPoint to design a SharePoint tab in Microsoft Teams as long as the site you're embedding the SharePoint page from has ShortPoint installed.
You can check out more information about ShortPoint for Teams in this collection of articles.