The term typically refers to the map data files compatible with iGO 8, iGO Primo, and iGO Nextgen software.
However, be careful when downloading files from unknown sources, as they may contain viruses or malware that can harm your device. TomTom TeleAtlas Map File Guide | PDF - Scribd
While the .fbl file is the actual map, a complete navigation experience often requires "supplementary" files found in the same map pack: iGO Map and POI File Setup Guide | PDF - Scribd