As of my knowledge cutoff in September 2021, Cisco does not provide an official UnityPackage format SDK for Unity projects. Cisco offers various SDKs and APIs for different purposes, including the Cisco Unified Communications Manager (CUCM) API, which allows integration with CUCM for call control and telephony features.
However, Cisco's SDKs and APIs are typically provided in the form of software development kits (SDKs) or application programming interfaces (APIs) specific to the platform or language you are developing with. They are usually not packaged as UnityPackage files specifically for Unity projects.
To integrate Cisco functionality into a Unity project, you would typically need to use the appropriate Cisco SDK or API, and then manually integrate it into your Unity project by following the documentation and guidelines provided by Cisco.
I recommend visiting the official Cisco Developer Portal (developer.cisco.com) for the most up-to-date information on available SDKs, APIs, and integration options for Cisco products and services. You can search for specific SDKs or APIs related to your requirements and explore the provided documentation, samples, and resources to assist your development team in achieving the desired integration with CUCM.