Welcome to Radio Reference from a another member in Macomb County!
Click on the link below. It will take you to the Radio Reference Database for Macomb County, MI, that is part of the MPSCS (Michigan Public Safety Communications System).
Scanner Frequencies: Michigan Public Safety Communications System (MPSCS) Trunking System, Statewide, Multi-State
If you scroll past the tower/frequencies, you'll start seeing the Talk Group listings. Here is where you will find the tags you refer to, along with their descriptions.
Bill