MarsSeed [1] filed a deletion request for ros-noetic-roscpp-core [2]: Defunct, unused, EOL package from 2021. ROS1 Noetic is reaching its EOL too, and the majority of its libraries are no longer compatible with Arch Linux, only with Python 3.9 and the already EOL Ubuntu 20.04 and Qt 5.12. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/ros-noetic-roscpp-core/