TextEditors uses the UseMod Wiki package. I must say: it was painless to use.
[UseModWiki], by Clifford Adams was based on the code of AtisWiki? by Marcus Denker. AtisWiki? was based on CvWiki? by Peter Merel. CvWiki? was the first GNU-licensed wiki based on WikiBase?, the wiki engine of the first wiki, [WikiWikiWeb], by [Ward Cunningham] launched in 1995.
See the [text formatting rules] on the UseModWiki? site.