Agent uses Sqlite3 database. You can view and alter data with sqlite3 command line tool. On most distros 'aptitude install sqlite3' will install it. Usage of the slqite3 comandline is simple. '$ sqlite3 <path-to-home-folder>/.hipagent/database.db' will start the command line tool with the correct database. You can check the contents with simple select querys and so on. You can get more information on the program from its man page (man sqlitebrowser).
Alternatively you can use the graphical user interface called sqlitebrowser. On most Linux distros 'aptitude install sqlitebrowser' will install it. To start it write to the terminal '$ sqlitebrowser <path-to-home-folder>/.hipagent/database.db' and you should see the tables and their content from the UI. You can get more information on the program from its man page (man sqlitebrowser).
The database contains three tables: local, remote and groups. Local table contains local HITs and their names. Remote contains remote HITs and their names. It also contains some extra information like the group name. Group table contains groups name and information on the group like are these HITs to be accepted or not.