Minecraft wiki entry for Igloo, associated text: In Java Edition, if a number of items in the igloo furnace are smelted, the light generated melts the igloo window, turning the ice into a water source block. This is intentional.[3]
Igloos are internally classified as a temple.‌[Bedrock Edition only]
The igloo is the first structure to use signs with text on them.
As of Village and Pillage, igloos with basements can be easily registered as villages, due to having one villager, a bed, and brewing stands and cauldrons, which count as job sites. However, the villager needs to be freed from the iron bars to claim a job site, or the zombie villager cured and freed, to be able to register as a village.
This also means raids can be triggered on the igloo.
It is possible for an igloo to generate on a cliff or other incline, causing its secret area to be wholly or partially exposed.