What is the purpose of the holes marked Do Not Cover on hard

Lockout Hasps - Non Conductive Nylon Hasp Red 3 Holes 3mm Shackle

Locations of four holes (marked from A to D) drilled on the HDD

DOT Limescale Descaler - Decalcifier 50grams

Hultafors Deep Ink Marker Black - FaceLine Inc Store

Drill a Hole in Wood Without Splintering (5 EASY Ways!)

4 Ways to Cover a Hole in a Wall - wikiHow

Marks on bathtub from plastic toys Have scrubbed as hard as

What is the purpose of the holes marked Do Not Cover on hard

Planet Platinum Stainless Steel Folding Towel Rack for Bathroom (2