/usr/share/publican/Common_Content/ is in publican-debian 0.3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/publican/Common_Content/debian/
/usr/share/publican/Common_Content/debian/defaults.cfg
/usr/share/publican/Common_Content/debian/en-US/
/usr/share/publican/Common_Content/debian/en-US/Legal_Notice.xml
/usr/share/publican/Common_Content/debian/en-US/css/
/usr/share/publican/Common_Content/debian/en-US/css/overrides.css
/usr/share/publican/Common_Content/debian/en-US/images/
/usr/share/publican/Common_Content/debian/en-US/images/image_left.png
/usr/share/publican/Common_Content/debian/en-US/images/image_right.png
/usr/share/publican/Common_Content/debian/overrides.cfg
/usr/share/publican/Common_Content/debian/publican.cfg
/usr/share/publican/Common_Content/debian/xsl/
/usr/share/publican/Common_Content/debian/xsl/epub.xsl
/usr/share/publican/Common_Content/debian/xsl/html-common.xsl
/usr/share/publican/Common_Content/debian/xsl/html-single.xsl
/usr/share/publican/Common_Content/debian/xsl/html.xsl