Packages for common geometric calculations including the ROS transform library, "tf". Also includes ROS bindings for "bullet" physics engine and "kdl" kinematics/dynamics package.
To the best of my knowledge this library should not exist and most definitely should not be installed by two entirely unrelated packages that make no explicit mention of it.
As the library does not exist in melodic on Ubuntu 18.04, it might be related to a change in python3.
I can see the library in a (non-Ubuntu) melodic workspace built on python3 as well, but cannot easily verify where it came from in that workspace.
This leads to strange package conflicts in released packages (Cross-post of https://github.com/PR2/pr2_mechanism/issues/343).
To the best of my knowledge this library should not exist and most definitely should not be installed by two entirely unrelated packages that make no explicit mention of it.
As the library does not exist in melodic on Ubuntu 18.04, it might be related to a change in python3. I can see the library in a (non-Ubuntu) melodic workspace built on python3 as well, but cannot easily verify where it came from in that workspace.