User property mappings between local AD, Azure AD and SharePoint Online?

I'm having trouble finding out property mappings from local AD via Azure AD landing in the SharePoint Online User Profile Service.

For example, how would I track down what the equivalent property of the SharePoint Online User Profile Service property "People:SPS-Location" is in Azure AD as well as local AD?

We're using Azure AD Connect to sync user objects to Azure AD which in turn get picked up by the SharePoint Online User Profile service.

Thanks for your advice.