Sage 1.5.2 fails to load, complaining about a missing sage.xul

[turmoni]

Given that I seem to be the only person having this problem, I'm intrigued as to what I'm getting wrong, but sage 1.5.2 doesn't work for me; I get:

File not found
Firefox can't find the file at chrome://sage/content/sage.xul.

in the sidebar.

Doing a diff between 0a1d4901ba3855d8dd8e678e02ee925cf5842e9c and dfdd46838a7824a81a4f1c43f45a09116d8f2b4d , I see that sage.xul replaces sidebar.xul, however when I download the XPI from https://addons.mozilla.org/firefox/downloads/file/223691/sage-1.5.2-fx.xpi and unzip it, I can't see sage.xul anywhere.

Currently, this is on Firefox 24 on Ubuntu 13.04.