Compared to LIC files, LYC files have a particularity
- the first four bytes represent the decimal value 2
- the next four correspond to the size of the file minus the first 8 bytes
Which does not exist in LIC files.

The rest is only the content of the licenses allowing the use of the files associated with the maps

renaming a LIC file to LYC can cause iGO to recognize it as an invalid format file and simply consider that it should be ignored, which may be the reason why iGO no longer crashes after the extension change