One minor note: jekyll definitely was not first to introduce front matter (though they may have introduced yaml front matter?).

I am sure that at least pyblosxom had it earlier: https://pyblosxom.github.io/Documentation/1.5/writing_entrie...

Here's the earliest surviving commit showing blog entry front matter in 2002: https://github.com/pyblosxom/pyblosxom/blob/f80cdb42eb37ee0e...

My recollection is that blosxom (a perl blogging engine) had front matter as well, but I can't find any evidence of it.