.S3Z File Extension

Compressed .S3M audio module file used by Scream Tracker 3.0, a multi-track sampler and sequencer application; contains sound samples and music patterns, which specify what notes are played back by the samples; supports up to one hundred 8-bit samples and 32 channels.

Since S3Z files are compressed with Zip compression, you can decompress the original S3M file with any Zip decompression utility.