I also had connectors like that, I traced back to a junction box so right side of cooker
fitted a light bar, but left was still working so that was done latter, same wall fused connection unit feeds both junction boxes but wanted to fit Lidi colour changing strip lights so fitted a socket where it would not normally be seen
not really what should be done
but since visitors will not know it exists unlikely to use it, and is protected with the fuse in the FCU, so net result
however I know whole house is protected by RCBO's and who ever fitted the cupboards were kind enough to fit junction boxes, and the surround is low enough to hide the socket.
With most work it is a compromise, used water pump pliers to squeeze the cable clips in place so not relying on sticky back which came with strip lights. And there is the option to turn strip lights to white but needed phone. The big problem is so many lights come with wallmart power supplies so need a 13 amp socket, had I been installing the cupboards I would have put the sockets above the cupboards, but not the access, some day we will have a new kitchen and I will fit more sockets and tile around them, but not ready to remove tiles yet, so have to work with what I have.
The plug could be 230 volt, and I would be looking for a class II set of lights not requiring an earth until such time as the kitchen is refitted, at which point clearly you re-wire as required before you fit any units. You seem to be saying you are doing that now, so once all units are off the wall, you will likely see how it was wired, then is the time to take pictures and ask any questions, while the units are in place it is anyone's guess what is there.