-* Sphinx makes use of [Blockdiag](https://pypi.python.org/pypi/blockdiag)
- for some of the diagrams; you'll need that too.
+* [Blockdiag](https://pypi.python.org/pypi/blockdiag) is used for some of
+ the diagrams.
+
+* To create the HTML version, you'll need a recent (>=0.7.8) version of the
+ [Alabaster](https://pypi.python.org/pypi/alabaster) theme.