Heretic E6

Does anyone have any info on the three super-secret levels of Heretic (E6M1-3)? Why are they there? Why are they untitled? The first level seems like a showcase of all the monsters and items or something.

The first looks like a Heretic-ified version of the Raven or id Software offices. E6M3 is a rehash of an old Doom deathmatch map made by American McGee (I believe that's who it was... I think the original is called idmap01.wad). Not sure about E6M2. They were put there for fun, and as deathmatch-only maps that wouldn't fit into the regular episodes. There was a thread about this a month or two ago, if you look back in the archives you might be able to find it.

A crappy source port called Wheretic had these names in:

E6 is called 'fate's path'
E6M1 is called 'offices'
E6M2 is called 'water shrine'
E6M3 is called 'american's legacy'

I read somewhere that one of them is the same as (or very similar to) a supersecret level E4M1 that appeared in the original 3-episode Heretic. I can't confirm that though.

I didn't think they were bad levels at all (a bit variable, but a decent challenge on skill 5 with a wand start), though the lack of an exit in E6M3 had me puzzled for quite a while.