The describe database consists of two files. The first is a specially formatted ASCII file, known as the database "source" file. It can be manually edited with any text editor, or updated with descu(8). It doesn't really matter where on your system this file resides, but the path /usr/lib/describe.src is recommended.
The second file is the compiled database file. This file is compiled from the source file by the descc(8) program. It is a binary file and not human-readable. Unless the DESCDB environment variable has been set, this file must have the pathname /usr/lib/describe.db.
Both files are available here: