Jack wrote:

Will placing a hot pot or dish on a glass refrigerator shelf crack it,
or is the glass specially treated to make it crack proof from heat?

Those shelves are made of tempered glass, not low-expansion Pyrex, and
can easily crack if something hot touches them. Also doesn't your
wife/girlfriend or mother prohibit you from setting anything made of
metal, glass, or ceramic directly against glass shelves because they
can get scratched and even crack? Sometimes it takes just a small
scratch to cause a crack, and a piece of tempered glass will burst
into thousands of tiny pieces when cracked.