This is a mount for RJ45-Ethernet cable splitter.
There are various models from different vendors in online shops that look all the same.
So I guess they all fit.

Both splitted ports are numbered.
You can also print and stick two 9 x 39 mm labels.

Use 4mm countersunk wood screws.

Creality

Ender 3

No

Yes

0.2

15

Print in the shown orientation (screw holes on the print bed) so the top of the model gets printed nicely.

Nozzle: 0.4 mm
Support Desity: 10 %
Support X/Y Distance: 1.2 mm
Wall Line Count: 4

Layer hight 0.4 mm should work, too.