Herobrine is the subject of a community-made creepypasta. He is one of the major community icons of Minecraft. Herobrine has not been present in any version of Minecraft.
"Canon" of Herobrine is widely regarded as the first image/story ever posted about Herobrine, as well as the Brocraft stream. Anything posted after these two events are considered as fanmade adaptions/variations.
He can be briefly seen during the final battle.