Custom Connector for Timeline documentation

[piboke]

Hi, I am working on custom connector for Timeline and I found this repo: https://github.com/microsoft/PowerApps-Samples/tree/master/model-driven-apps/custom-connectors/SecondaryRecordSource/solution

Unfortunately, there's no documentation on how to use it. There's an Interfaces.d.ts file which references mscrm.d.ts but there's no information where to pull it, how to use them etc. It looks like an extract from some internal project without any context. Could you please share some more info?

thanks, p.