Usage of 'rosdep keys' argument is unclear from documentation

[firesurfer]

I am currently trying to debug why xacro is not picked up as a dependency from a package (aka not installed in the ci pipeline).

According to the documentation the rosdep keys command can be used to list all dependencies of a package.

rosdep keys ...
list the rosdep keys that the packages depend on.

When i now run:

rosdep keys --from-paths ./src <my package name> from the root directory of my local workspace I always get the error:

given path '<my package name>' does not exist

The official documentation: http://docs.ros.org/en/independent/api/rosdep/html/commands.html only provides the same information as the rosdep --help command.

Also the guide in the "normal" documentation: https://docs.ros.org/en/jazzy/Tutorials/Intermediate/Rosdep.html does not provide any further information.

Question

So the question is:

1. How do list all dependencies of a package
2. Can I also check if these dependencies are installable