When otclient initializes it tries to find all .otpkg files inside the
current search paths (./ ./modules ./addons) and then add them
to the front of current search paths. This way .otpkg can contains
many modules/addons and modifications in a single file that otclient
can recognize.
otpkg files can be compressed files supported by PhysFS, which
are ZIP (.zip) and LZMA (.7z).
Henrique Santiago