TSComp
From Just Solve the File Format Problem
The Stirling Compressor (sometimes called "TSComp") is a compressed archive utility for DOS, and associated file format, developed by The Stirling Group. It uses PKWARE DCL Implode compression.
It's not clear if it has a conventional filename extension. The software does not provide one.
Identification
Files begin with bytes: 65 5D 13 8C 08 01
.