Where is the hybrid local gateway for cloud calling deployed?

Cisco UCM is an on-premises call control platform; while it can integrate with cloud calling, it's not where the hybrid local gateway for cloud calling is deployed. The CUBE would connect to UCM or directly to the PSTN.

In Cisco Webex Cloud Calling deployments, the hybrid local gateway functionality, which allows cloud-registered users to access on-premises PSTN connections or integrate with existing PBX systems, is typically implemented on a Cisco Unified Border Element (CUBE) device. CUBE acts as the demarcation point for SIP trunks, providing security, interoperability, and call routing between the Webex cloud and the local voice infrastructure.

Cisco Expressway-C connector hosts are used for Mobile Remote Access (MRA) and B2B calling, providing proxy services for Jabber clients or intercompany calls, but not for the local gateway functionality of Webex Calling to PSTN.

Cisco Webex Control Hub is the cloud management portal for Webex services; it is where the gateway is configured and managed, but not where the physical or virtual gateway device is deployed.