move_base_msgs for Melodic missing

[Raspberry Pi 4, Ubuntu 18.04.3 LTS (64bit), ROS Melodic]
HI, I'm trying to build the rosplan_stage_exploration_demo, but catkin build returns a CMake error stating it can't find move_base_msgs. Where/how can I get this package?
I have the files from a previous ROS Hydro install on another hard disk. Can I reuse them here for my Melodic setup? (All the files look like they are interpreted.)
    ~/ROSPlan$ catkin build
    ------------------------------------------------------
    Profile:                     default
    Extending:          [cached] /opt/ros/melodic
    Workspace:                   /home/user/ROSPlan
    ------------------------------------------------------
    Build Space:        [exists] /home/user/ROSPlan/build
    Devel Space:        [exists] /home/user/ROSPlan/devel
    Install Space:      [unused] /home/user/ROSPlan/install
    Log Space:          [exists] /home/user/ROSPlan/logs
    Source Space:       [exists] /home/user/ROSPlan/src
    DESTDIR:            [unused] None
    ------------------------------------------------------
    Devel Space Layout:          linked
    Install Space Layout:        None
    ------------------------------------------------------
    Additional CMake Args:       None
    Additional Make Args:        None
    Additional catkin Make Args: None
    Internal Make Job Server:    True
    Cache Job Environments:      False
    ------------------------------------------------------
    Whitelisted Packages:        None
    Blacklisted Packages:        None
    ------------------------------------------------------
    Workspace configuration appears valid.
    ------------------------------------------------------
    [build] Found '18' packages in 0.0 seconds.
    [build] Updating package table.
    Starting  >>> occupancy_grid_utils
    Starting  >>> rosplan_demos
    Starting  >>> rosplan_dispatch_msgs
    Starting  >>> rosplan_knowledge_msgs
    Finished  <<< rosplan_dispatch_msgs                         [ 10.2 seconds ]
    Finished  <<< rosplan_demos                                 [ 9.8 seconds ]
    Starting  >>> rosplan_rqt
    Starting  >>> rosplan_sensing_interface
    Finished  <<< rosplan_knowledge_msgs                        [ 11.0 seconds ]
    Starting  >>> rosplan_stage_demo
    Finished  <<< rosplan_rqt                                   [ 0.8 seconds ]
    Starting  >>> rosplan_stage_exploration_demo
    Finished  <<< rosplan_sensing_interface                     [ 0.7 seconds ]
    Starting  >>> rosplan_stage_waypoint_demo
    Finished  <<< rosplan_stage_demo                            [ 10.1 seconds ]
    Starting  >>> rosplan_turtlebot2_demo
    Finished  <<< rosplan_stage_exploration_demo                [ 10.3 seconds ]
    Finished  <<< rosplan_stage_waypoint_demo                   [ 10.3 seconds ]
    Finished  <<< rosplan_turtlebot2_demo                       [ 10.1 seconds ]
    Starting  >>> rosplan_turtlebot3_demo
    Starting  >>> rosplan_dependencies
    Finished  <<< rosplan_dependencies                          [ 3.6 seconds ]
    Starting  >>> rosplan_knowledge_base
    Starting  >>> rosplan_planning_system
    Finished  <<< rosplan_turtlebot3_demo                       [ 9.4 seconds ]
    Finished  <<< rosplan_knowledge_base                        [ 8.2 seconds ]
    Finished  <<< rosplan_planning_system                       [ 8.2 seconds ]
    Starting  >>> rosplan_interface_movebase
    ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
    Errors     << rosplan_interface_movebase:cmake /home/user/ROSPlan/logs/rosplan_interface_movebase/build.cmake.000.log
    CMake Error at /opt/ros/melodic/share/catkin/cmake/catkinConfig.cmake:83 (find_package):
      Could not find a package configuration file provided by "move_base_msgs"
      with any of the following names:

        move_base_msgsConfig.cmake
        move_base_msgs-config.cmake

      Add the installation prefix of "move_base_msgs" to CMAKE_PREFIX_PATH or set
      "move_base_msgs_DIR" to a directory containing one of the above files.  If
      "move_base_msgs" provides a separate development package or SDK, be sure it
      has been installed.
    Call Stack (most recent call first):
      CMakeLists.txt:6 (find_package)

    cd /home/user/ROSPlan/build/rosplan_interface_movebase; catkin build --get-env rosplan_interface_movebase | catkin env -si  /usr/bin/cmake /home/user/ROSPlan/src/rosplan_demos/rosplan_demos_interfaces/rosplan_interface_movebase --no-warn-unused-cli -DCATKIN_DEVEL_PREFIX=/home/user/ROSPlan/devel/.private/rosplan_interface_movebase -DCMAKE_INSTALL_PREFIX=/home/user/ROSPlan/install; cd -
    ....................................................................................................................................................................................................................................................
    Failed     << rosplan_interface_movebase:cmake              [ Exited with code 1 ]
    Failed    <<< rosplan_interface_movebase                    [ 8.8 seconds ]
    Abandoned <<< rosplan_interface_mapping                     [ Unrelated job failed ]
    Finished  <<< occupancy_grid_utils                          [ 1 minute and 32.4 seconds ]
    [build] Summary: 14 of 16 packages succeeded.
    [build]   Ignored:   2 packages were skipped or are blacklisted.
    [build]   Warnings:  None.
    [build]   Abandoned: 1 packages were abandoned.
    [build]   Failed:    1 packages failed.
    [build] Runtime: 1 minute and 32.7 seconds total.
    [build] Note: Workspace packages have changed, please re-source setup files to use them.
KCL-Planning / rosplan_demos

move_base_msgs for Melodic missing #26
