http://breezewiki.pjsfkvpxlinjamtawaksbnnaqs2fc2mtvmozrzckxh7f3kis6yea25ad.onion/minecraft/wiki/History_of_textures/Unused_textures
Doors were ultimately added on the 7th of June, 2010 , as a relatively normal block, which would instantly open or close when interacted with, having no continuous animation in the process as had been mentioned. However, the /item directory in minecraft.jar , which stored the textures for other non-mob entities at that time such as minecarts and arrows , gained a texture called door.png in this same version, which is without a doubt linked to said opening/closing...