"Esri created the file geodatabase to be a container for storing multiple attribute tables, vector and raster data sets. It’s the successor of the personal geodatabase (MDB) – and Esri recommends file geodatabases over personal geodatabases.

File geodatabases offer structural and performance advantages. They have fast performance, versatile relationships, compatible storage for rasters, improved spatial indexes, data compression, customizable configuration, and 1 terabyte file size restrictions.

Within a geodatabase, geographic datasets are referred to as feature classes. But geodatabases can store more complex data such as networks, raster mosaics, and feature data sets." (from https://gisgeography.com/gis-formats/)

See the following for more information:

• DANS info
• x-filegdb info