> Does Ruby Carats do the same thing as Gabriele's extensions?

Gabriele's? Do you mean Gavins? Or is this another set of extensions I
am not aware?

Ruby Facets is the extensions library, which is unique for its
atomicity.

Ruby Carats OTOH, is an extensive collection of Classes, Modules and
Mixins (but has not yet been released.)
See http://calibre.rubyforge.org/