Little to no documentation that makes integrating this system extremely painful

I inherited a website that uses this plugin, and the lack of documentation makes it extremely painful to integrate. Outputting something simple like a user avatar makes you loop and output through an email, and the only way to find that out is to google other people’s struggle. Most plugins that are extensive like this, should have good documentation on use. This plugin has one page referring to three functions and then tells you to look through the php file.