Where (in Foundation) can I find the SharePoint tables/lists containing the users as found under People and Groups?
This can be achieved by performing one of the below steps.
1) Foundation Site - Users- All users here you can see the list.
2) Or in the Database where LMS is installed - Under LMS db there is table dbo.userinfo in that table information is stored . Right click on the table and click on show top 1000 rows.