Wolf-Extra is a mod for registered Wolfenstein, made by Poet. It was released on November 7, 1999.
The mod showcases some of the first mapping that Poet made; compact, difficult designs utilizing very little of the 64x64 slate all the while making for quite a challenging and imaginative gameplay. The original DOS version features new levels on Episodes 1, 2, 3 and 6, with Episode 4 featuring one proper finished level.
Most of, if not all of the maps were inserted into Enemy Around the Corner, which is available in SDL. Tweaks were made to some of the maps, however.
In June 2019, Poet mentioned that he no longer had the original set at hand, and a work of research was begun. Eventually Arielus found the set in his massive collection of mods, and it was shared with Poet who then hosted the set on his own website, in addition to the set being released in its own DHW thread.