This was made in 2018 for the Original Ender 3. It may work for current/newer versions but I can't confirm it.
This will smooth out the passage on the 20x40 frame underneath the bed where the cables sit to prevent them from rubbing on the sharp edges of the frame.
Simple push fit design.
Rotate the model in Cura like I've shown in the pic before printing.
(Last picture is upside down and wouldn't allow it to be rotated)
Doesn't fit the Pro model. Check comments on Thingiverse for scale suggestions
https://www.thingiverse.com/thing:2934313/comments
The author hasn't provided the model origin yet.