Heh, all 11 sites! It only had 4 sites in it when I joined, so my three sample sites in the editor application virtually doubled the category overnight.
This is an area of the directory that receives a figure of nil tending towards zero submissions from the outside (except some strange Brazilian business parks, or real estate spam {yeah, really!!} from time to time), so most of the categories in that area have been built by editor suggestions, and from submissions from the inside. Of course, if anyone has any useful standards related stuff they want to submit then note that the "submit to listing time" is usually measured in days rather than months; however, sites really do need to be on topic with the category (just like in the rest of the ODP), but as a category will contain at most 3 or 4 unreviewed sites anything wrongly submitted or trying it on is blatently obvious; hint: there is nothing selling anything anywhere near there.