It’s there. Really.
When you tile around a jacuzzi or heated tub you need to have an access panel in order to work on the motor or heater or fix any problems that may suddenly appear with your brand new fancy-pants uppity bathtub. You also need access to any outlets. This is required by code – DON’T SKIP IT!
Many bathtubs can have access panels on the backside of the wall in a closet or something similar right next to the bathroom.
If you have a tub like the one pictured there – this isn’t always possible. When that’s the case you need to create one in the tile installation itself and magically make it disappear so no one knows it’s there.
This is how I do that.