MarsSeed [1] filed a deletion request for ros-melodic-openni2-launch [2]: Fails to build. Abandoned since 2021, flagged since 2022-07 for the last point release from Apr 12, 2022.
Otherwise this is also EOL, with all ROS Melodic distro packages. No one uses this and nothing depends on it. Safe to delete. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/ros-melodic-openni2-launch/
