wmatrix currently requires the "old stable" version of pybottle (0.11.X).
We should port it to the latest stable version (0.12.Y, see http://bottlepy.org/docs/0.12/), so that we can use official Gentoo ebuild, and get better support in the long run.
ntang@ said as a comment in a doc:
"""On my desktop, I have 0.12.8 by default, it choked on the templates - mainly the "rebase" function syntax changed."""
There might be other issues...
Comment 1 by autumn@chromium.org
, Mar 14 2016