From Just Solve the File Format Problem
ARHANGEL is a compressed archive utility for DOS, and its native .LG file format, developed by George Lyapko (also written "Lyapko George"). It was distributed as shareware. Its name is derived from "ARchive HANdler by GEorge Lyapko".
Based on the warnings in the change log, you probably shouldn't expect much compatibility between different versions.
Lyapko also developed LGHA, an optimized archiver for HA format. The ARHANGEL credits suggest that ARHANGEL may have been inspired by HA.
Files created by v1.40 start with ASCII "
- 2009 archive of ARHANGEL website