That is what I have already found out.
In Tableau our users are mostly using 4 entities: Workbook, Dashboard, View, Datasource. In terms of Datahub Dashboard is a Dashboard, View is a Chart, and Datasource can be represented as a Dataset (with some assumptions). No correspondence for Workbook, which is an entity with several Dashboards and Datasources.
About ingestion - I'm using tableauserverclient python module to get the data, Tableau Server allows you to get some meta-information directly from the objects (names, tags, urls and so on), but for additional information (like list of datasources and sql code) I had to download xml-files and parse them. It requires admin user and a generated token.
P.S.: I've never used Tableau before and it brings me a lot of pain, and I may be missing something obvious 😅
Hope that starts some action cat on keyboard