PEP (Prediction-Encoded Pixels)
From Just Solve the File Format Problem
PEP (Prediction-Encoded Pixels) is an experimental compressed image format. It was developed by an entity named "ENDESGA". It uses Prediction by partial matching.
Identification
As of v0.3 of the reference software, the file format doesn't appear to have any signatures, or any easy way to identify a file from its contents.