The wiki says that every 20 minutes the wandering trader has a 7.5% chance of spawning within 48 blocks of the player, but:
Does the normal "not within 24 blocks of spawn point" rule apply?
Does he only spawn on opaque, full blocks?
Can the odds be increased by making multiple layers he can spawn on?
How is it determined whether the player is "underground"?
How does it work differently in multiplayer? The wiki just says "the player"