Project invoice proposals of Exact Online

I am looking for invoice proposals of projects. During project execution these generate actual invoices for the customer on the project.

Is there some Invantive SQL table for it?

The name is a little confusing, but yes, they are available:
ExactOnlineREST.Project.InvoiceTerms

For example, these are the contents of our development environment:

Please see this topic @hans.jansen and the related topic Project cashflow of Exact Online projects based upon invoice terms to be invoiced / already invoiced.