Koldovstoretz is one of the eleven wizarding schools registered with the International Confederation of Wizards.
Etymology: The name is a combination of the Russian words колдовствó (koldovstvó) meaning "magic, witchcraft, wizardry" and either творéц (tvoretz) meaning "creator" or дворéц (dvoretz) meaning "alcazar (royal palace)" (dict.com Lingea: Russian-English).
This school is mentioned in the Book of Potions videogame, produced by Sony from information provided by J K Rowling. It was also included in a section of "Information from Pottermore" in the new editions (2014-15) of the Harry Potter books. However, it has not yet been added to the collection of Wizarding Schools on the Pottermore website: Collection: Wizarding Schools.
According to the 2014 Children's Edition of the Potter books (BCE), students here play a broom game similar to Quidditch - but flying on uprooted trees rather than brooms. This fact is found nowhere else in canon, including Pottermore (which is where the children's edition ostensibly gets its information), which leaves it's canonicity in question.
From the Web
Video walkthrough of the Book of Potions game: YouTube: Book of Potions videogame