RAX (compressed archive)
From Just Solve the File Format Problem
RAX (Romanian Archiver eXpert) is a compressed archive utility for DOS, developed by GeCAD.
It supports multi-volume archives, in which case each volume is given a unique filename extension, starting with .RAX, then .X00, .X01, ...
Identification
RAX files begin with bytes 'U' 'L' 'E' 'B' 0x0a
.