Extensible Storage Engine
Extensible Storage Engine (ESE, EDB, ESEDB), also known as JET Blue (no connection with the airline) is a database engine from Microsoft used as the back-end database of a number of its products, and eventually a public API was released for it. .edb and .sdb files are used for database storage, and .stm for a streaming file. There are a number of different versions.
The method of database storage is ISAM (Indexed Sequential Access Method).
An earlier and slightly different Microsoft database engine is Jet Red, which supports file sharing.
These signature bytes appear at offset 4:
ef cd ab 89
- libesedb (tools for accessing ESE databases)