/usr/lib/python2.7/dist-packages/chameleon/tests/inputs/066.xml is in python-chameleon 2.6.1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 | <!DOCTYPE doc [
<!ELEMENT doc (#PCDATA)>
<!ATTLIST doc a1 CDATA #IMPLIED>
<!-- 34 is double quote -->
<!ENTITY e1 """>
]>
<doc a1="&e1;"></doc>
|