Just want to add this to the ""funny"" answers about cracked glass.
Maybe some are just joking about safety but I think that we are never too prudent when burning a stove.
A gap intentionnally made at the top or bottom of a stove's glass in one thing and a no-problem and has no link with a cracked or damaged glass.
Serious stoves makers like : Vermont Castings, Harman Stoves and many more write in the owner's manual: ""If a glass is broken or damaged, do not operate the stove until it has been replaced"", from Harman Stoves TLC 2000 manual, Section Operation, P.8
