Metakit has its own (closed, read-only) Wiki [L1 ] and home page [L2 ]. Metakit is the persistence engine for Wikit, of course.
The Metakit File Format.
The Tcl binding to Metakit is named Mk4tcl.
It was claimed here that Mk4tcl is part of the ActiveTcl Batteries included release. This does not appear to be the case as of 8.4.2, 9 May 2003 - Roy Terry. Metakit is included in lib/mk4tcl as of tcl 8.4.4, but without documentation, it seems (Hof).
DGP For what it's worth, here are the points I found most useful in the Roseman intro:
"... many of the integrity checks required in traditional database use are not required in Metakit, because Metakit offers nested views -- a cleaner way to represent the relationships often enforced by integrity constraints."
"cleaner" is a matter of opinion, ask a relational database theorist. I don't want to start those arguments here, just point out that if you use Metakit for a complex system, you should design first, and be very careful. - EMJ
DKF: "You should design first"? That's actually true of any non-trivial program, you know... ;^) An ounce of thought saves a ton of effort.
MetaKit Viewer
See also dgmkviewer, a metakit viewer/editor in Tcl