I have heard that Subversion is integrated to Data Modeler. What does that mean and how can I see what is inside Subversion? I do not want to install any clients or anything…

Go to Team menu and select Versions. The Versions browser opens. You use this browser for creating directories to Subversion, working with Subversion and for seeing what is in Subversion. Go to Team menu again and select Pending Changes. The Pending Changes tab appears. In Pending Changes you check for incoming changes and update the working copy, commit outgoing changes and add files.

Subversion integration also means that when you are working on Pending changes you see the table etc names and not the file names. The file names are terrible for human eyes because they are based on object ids.