/etc/tomcat7/Catalina/localhost/solr.xml is in solr-tomcat 3.6.2+dfsg-8.
This file is owned by root:root, with mode 0o777.
It is a symlink to /etc/tomcat7/Catalina/localhost/../../../solr/solr-tomcat.xml
/etc/tomcat7/Catalina/localhost/../../../solr/solr-tomcat.xml