XLR to RJ45 Keystone Jack adaptor plate.
It does what it says.
Screw on the back of a D series XLR pane hole and push in any Keystone RJ45 socket.
Print large side down, There is a sacrificial bridging layer to avoid need for any support, just cut it out with an X-Acto knife and it's ready to go.
You may want to run a 3mm tap through the screw hole to clean them out.
The author hasn't provided the model origin yet.