https://www.freedrinkingwater.com/products/ro-hi-detail

Probably because sour would make your lips pucker? I think lemons would be more obvious.

Personally I would include it just so that the next homeowner doesn’t curse you when they go to drill something into an expected stud that isn’t there.

Try threading a wood screw into the hollow pin until it grabs, and pull it out while twisting with a pair of pliers.

How would someone get started doing this?