GID, Windows Help Global Index File (.gid)
The GID Settings file format
A file with a GID extension is created the very first time a user searches Windows Help in an older version of Microsoft Windows (95 and 98). The file was used to improve the access and indexing of search topics in Windows Help.
Technical details of GID files
Not much is known about the specifications of the GID file. It is created automatically by Microsoft Windows when searching in Windows Help.