These are the comics that were posted on xkcd where the release date is unknown.
- comic #36 was originally posted as a duplicate of comic 10: Pi Equals.
- This was corrected some time between April 22, 2006 and July 5, 2006 when the current version 36: Scientists showed up in the web archive (see the links). See also the trivia section for that comic.
- There has so far been no way to determine when Randall made the correction, and thus posted the comic.
- The Unpublished Five Minute Comics was released as an oversight of someone on one of the unofficial xkcd browsers for Android, instead of the correct comic 940: Oversight.
- Since this has never been released officially by Randall, it cannot have a date (yet). But it was probably drawn in 2010 as the other three were released in November 2010.
- If the browser released it on the same day as comic 940 is at present unknown. And thus the date of that comic August 19, 2011, also makes no sense to place on the unpublished comic.