The "Core API Keys" are created by the tenant administrators via the End Customer portal, under "Settings -> API Keys"
All Core API Keys have full access to the End Customer tenant.
These keys are used to Authorize all API requests to the tenant.
Multiple Core API Keys
An unlimited number of Core API Keys can be added to a tenant. It is recommended to create a new key for each integration used. This will allow to revoke keys from older and retired integrations to preserve security without affecting other active integrations.