This is an eurorack cable organizer. Mount it on top of modules and pull cables under it - or group them by signal kind.
Mounting holes are always a multiple of an eurorack HP.
Supports countersunk screws, defaults to M3 mounting holes.
Inspired by ADDAC's bent alu profiles - photos are his.
You can get away with flanges and wedges that aren't a full multiple of 1 HP, as long as they sum up to an HP multiple.
Try enabling "debug eurorack rail" to see the pattern of holes.
The author marked this model as their own original creation.