There were several levels of limbo, according to medieval thought (but not Church Doctrine). One for people who committed wrongs but still lived acc. to God and so needed to wait until Jesus returned to get into Heaven (Patriarchs) and one for the Unbaptized/those who died too young to have sinned yet (Infants - this one is the not canon limbo. The fanon limbo, if you will). This was in addition to Purgatory, which was a different thing, and Hell, which was yet another different thing.
In high school I took a religion class and a priest came in to answer questions (it was actually very fascinating, he blessed holy water for one kid) and he was talking a bit about limbo, i think mostly talking about the first one, and I asked a question about what happens to the unbaptized, not the ones who never had the opportunity (like infants/people from cultures who didn’t hear about Christianity) but to people who just...didn’t want to be baptized (me) and he very very awkwardly skirted around telling me ‘you’re going to hell’ which I honestly didn’t mind, but it was an interesting interaction.