In Tcllib, a module containing many packages, at the core a plugin system for the handling of general text transformations. Around that a set of packages for parsing various types of grammar specifications and generating parsers for them (using grammar_me's implementation I of the ME virtual machine).
The packages have no documentation yet, only the page application based on them.
Appears to have been created by AK. In the source directory (tcllib/modules/page), there is a NOTES.txt file. Not terribly helpful, though.
In the subdirectory (tcllib/modules/page/notes/) there are more files. Also not terribly helpful.
There are some examples (not very simple) in tcllib/examples/page.