Depscan
What is Depscan?
Depscan scans ELF executables library dependencies and generates a nice dependency report for you. This makes it easier to find out what your software's, dependencies are.
Listaller uses this tool at build-time to generate the automatic dependency-list, but you may use it as well to find out why an application has dependency X.
Depscan will later be extended to support dependency-detection for other languages, e.g. Python/Ruby too.
How to use Depscan?
The documentation is not yet complete. You may want to help extending it.