XLD4 (maybe also called Q4) is a raster graphics format that was used mainly in Japan. An image consists of two files: a .q4 file, and a .q4d file.
Q4 files have ASCII "
MAJYO" at offset 11.
Q4D files begin with the ASCII "===============>>>>> XLD4 GRAPHIC DATA DOCUMENT <<<<<===============" and are in character encoding IBM-932/IBM-943