Here's an example:
The atlas is quite obvious what it does, but the .etc1 files are apparently Ericsson Texture Compressed? Could not find any tool that knew how to decompress them, not even sure what the format is AFTER they are even decompressed. Probably a simple one but I couldn't figure it out.
EDIT: SOLVED HERE: https://forum.xentax.com/viewtopic.php?f=18&t=17156