What is the purpose of entry **/tm.* in the includes section of the maven-clean-plugin configuration in hippo-cms7-project?

Because of this entry, and under Maven 2, project Thieme-Meulenhoff deletes files tm.cnd and tm.xml on mvn clean.
These files are obviously vital for the project to run. The xml contains the namespace entries.

Also this makes the two files appear under "Locally Deleted Files" in intellij, and this being irreversible (svn revert fails with a useless generic msg; depth=infinity fixes things)