Currently, using a freeform project, using http://netbeans.org/ns/freeform-project/1.xsd, the Task List module does not scan any files outside the java-data section, so far as I can tell.
In my view, it should search all folders declared as source-folders in the folder section. This way it would pick up @todo (etc.) notations in source files written in other languages.
If anyone else is struggling with this, I should mention that if one creates "fake" package-root elements inside a "fake" compilation unit one can get the desired behavior. But that seems an absurd workaround.
task list scans whatever files it gets from indexing infrastructure
*** This bug has been marked as a duplicate of bug 162580 ***