Help! Anyone knows what these wires do?

[Spir4]

Hello,

This is my first post on the forum. First of all thanks for having me
I was looking to "upgrade" my current e bike with a throttle. It doesn't have one at the moment (it works with a PAS sensor). To see if this is possible I've opened up the controller, but it's a bit of an unusual wire layout so I was hoping you guys could help me out.
This is how it looks like:


So basically I know what all the wires do except for the ones to the right. Here is a photo of that part in more detail:



So it has two connectors coming from the controller (one which has 4 wires (purple, red, green, white), and one with 3 wires (black, orange, red)). Those connectors meet in that small black box (which has nothing on it, no serial number, not anything). Then, 2 wires (black, red) leave that box and end up in a connector that isn't attacted to anything.
I've googled and googled but couldn't find anything. The type of controller is g3m20211-1592-16:



So my last hope rests on you guys, otherwise I'll just have to leave it as it is :-(

Thanks!