I on purpose removed all EOS pacakges and delete the entry about Endeavouros mirror in pacman.conf, but I still get the warning. Am I missing something?
Just run sudo pacman -R endeavouros-keyring endeavouros-mirrorlist eos-hooks eos-packagelist eos-plasma-sddm-config grub-tools grub2-theme-endeavouros yad-eos
to get rid of the packages and the warning.