I’ve never heard of a house having two kitchens. That house does not look so grandiose either, is it old? Was that something they did back then? Why?
The link also shows a photo from the back of the house. It’s a good size house.
Summer kitchen?
Big homes from the Victorian era were often subdivided in later times (i.e. Great Depression era) so that the owner could bring in extra income from a tenant (so a 3700 sq ft home could be turned into 2 x 1850 sq ft apartments). In the big cities, such a house could be turned into 4 x 925 apartments.