MarsSeed [1] filed a deletion request for ros-noetic-ros-core [2]: Unused, obsolete. ROS1 Noetic is now EOL. Most of this distro's applications are not compatible with Arch Linux anymore, only with the freshly EOL Ubuntu 20.04 LTS, Python 3.9 and Qt 5.12. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/ros-noetic-ros-core/