Stove glass can be expensive (£50-£100) and can break - sometimes without warning (thermic shock). It is not covered by any normal stove warranty from stove manufacturers. It can break on on day 3 or day 1,576 or never - it is not predictable.
To claim on glass warranty all we require is an image of the broken glass and a new one will be despatched.
We offer this in a desire to avoid heated discussions with customers who want free glass - it is too expensive :-)