I was mining in a snow biome, and I suddenly fell into a small igloo, which was furnished with a bed, furnace, and crafting table. There was no door, and the floor was covered with carpet. There was no village nearby. Even stranger, when I went to mine the carpet, there was a trapdoor underneath, which led down a short shaft. At the bottom of the shaft was a larger room with a cauldron, brewing stand, and a chest containing a few items. There were two small indents in the back wall of the room, one of which held a villager trapped behind iron bars.
Does anyone know what that structure is called? The version of Minecraft I was playing was 1.20.10.