Substub is an old category used in Wikipedia up until to got discontinued. Here, it means that a page is SO bad, or so incomplete, that even marking it as a stub wouldn't be sufficient.
“NOTE: This article is a stub, even by this community's standards. You can help by expanding it...Mm2wood
Pages in category "Substubs"
The following 15 pages are in this category, out of 15 total.