GoCAF (Go Containerized Azure Function) is a custom handler Azure Function deployed through the Azure Container Apps service.
Typically, the Azure Functions service natively supports a few different languages/frameworks namely dotnet, python, node, powershell and, as is the case, custom. The service also supports containers, but that is enabled through the licensing options and not the service "runtime" itself.
However, there is now support for Azure Functions to be deployed through the Azure Container Apps service. While it might be confusing at first, you are effectively deploying an Azure Container App which is explicitely optimized for Functions and not a native Azure Function which has been containerized. Refer to Azure Functions on Azure Container Apps overview for further details.