I accidentally let all the water boil off in my standard glass kettle (if it matters, it's a Medelco WK112 OneAll Stovetop Whistling Kettle). It didn't crack, and cleaned up fine.
But might there be a lingering chemical change that's left the glass unsafe? (E.g., is there anything it might leach into the water I'll be boiling day after day?)
As per the suggestion of @moscafj, I asked the manufacturer, which replied:
Hi- we do not recommend you to use that kettle any longer if it was boiled out dry as stated in our instructions."
But I am still interested in the question. (I'll get a new kettle to be on the safe side, but not because I "always trust the manufacturer.")