Lists installations of your GitHub App that the authenticated user has explicit permission (:read, :write, or :admin) to access.

You must use a user-to-server OAuth access token, created for a user who has authorized your GitHub App, to access this endpoint.

The authenticated user has explicit permission to access repositories they own, repositories where they are a collaborator, and repositories that they can access through an organization membership.

You can find the permissions for the installation under the permissions key.
List app installations accessible to the user access token