The Load FCC License Database menu choice makes an Internet Web query to the United States Federal Communications Commission (FCC) website to download the complete catalog of currently issued U.S. amateur radio callsigns, and copies the relevant information into a local database file stored in the YAAC log files directory. This database can be queried by right-clicking on a station on the map or in any tabular view that supports popup menus, and asking for Licensee Info.
Note that the FCC database snapshot file may be a couple months behind the Universal Licensing System's records, so extremely recent new licensees and/or upgrades may not appear when looking up license records.