The Quake remaster brings back a cut section of E2M6

When Quake was being developed, the developers at id set a self-imposed limit of 1.4MB for each .bsp file, meaning no map could go over the file size of a single floppy disk. To get E2M6, the Dismal Oubliette, down to that size its designer, John Romero, had to remove an area that was originally its entrance (though he later shared it online).

As Quake expert starshipwaters noticed, the recently released Quake remaster restores this lost entrance to its rightful place. Now, when you arrive in the Dismal Oubliette you’re at the bottom of a wet and winding cave and have to work your way up, past hellknights and other classic jerks of Quake, to get to what was previously the beginning of the level.

source: gamezpot.com