Where can I find the object schema for Bitbucket Connect install event?

Hi Community,

When I am installing the dev Connect app, I did receive the installation event object in the request. However, where can I find the schema of the object so I can understand what each fields suppose to be used?

We have

    "actor": {},
    "baseApiUrl": ,

(Value removed).

Specifically, when is the public key used? And what is the difference between principle and user (they both contain the same data with type “team”, but pointing to the workspace the app is installed).

Just pointing me to the documentation will be appreciated. The only thing I can find is App descriptor