These are Higo connectors, waterproof (or at least highly resistant) and getting more common.
THey just pull apart at the color rings; they're hard to unplug accidentally cuz it makes the water seal.
The ones with metal rings unscrew counterclockwise from each other on the ring itself, then pull the plugs apart. I've seen these mostly used on the LCD.
At least for small-signal stuff, I really wish Grin Tech (and everyone else) was using them; they're easy to get nowadays.
The panel-mount connectors available from
https://www.e-bike-technologies.de/index.php/en/connectors/higo
aren't too hard to solder wires to even with my eyes and hands, and they also have pre-wired cable sections that could be soldered or crimped to a junction box or each other or other wires or directly into controllers. If I had the money to do it I'd rewire the whole trike with these connectors for small things that need to be disconnected occasionally.