Pull the shelf away from the wall.
Thread the power strip through from a side.
Use one column of shelfs for connecting things to the power strip.
This way you can easily connect things to the power strip from behind.
Cables will be vertical and excess can be left hanging.
If you use the second row from below, you can easily connect things temporarily. But the lowest row would allow for a better look if the power strip is only used for permanently plugged devices.
Pull the shelf away from the wall.
Thread the power strip through from a side.
Use one column of shelfs for connecting things to the power strip.
This way you can easily connect things to the power strip from behind.
Cables will be vertical and excess can be left hanging.
If you use the second row from below, you can easily connect things temporarily. But the lowest row would allow for a better look if the power strip is only used for permanently plugged devices.