In Winter '20 release, Einstein Analytics introduces Salesforce Direct, read this release notes for complete info of Salesforce Direct.
However, Salesforce Direct offers you to get data more than just Salesforce objects, but data in Einstein Analytics too, one of them is EdgeMart, please not to confuse with the edgemart node in Dataflow.
Let's have hands-on, make sure you are in the Production org., EdgeMart object does not available in the sandbox at this moment.
1. Create a new Dashboard
2. Click Create Query button (if you do not see the button), click the blank canvas
3. Select Salesforce Direct as the data source
4. Type EdgeMart in search box
5. Select EdgeMart
6. Now you will be presented with Untitled Query with a bar chart with a count of rows, this row represent the number of datasets you have.
7. You can modify to table mode when as your needs.
The table above shows where is the dataset located, created by, last modified by, data refresh date, etc.
Reference: Show your data's refresh date with Salesforce Direct