Problems with the apt key ;) Dont know why ;)

For now use update.sh/CBuild_update script

Debian/Ubuntu - apt

Install ppa:

curl -s --compressed "https://cbuild.sourceforge.io/ppa/ubuntu/KEY.gpg" | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/cbuild.gpg > /dev/null
        sudo curl -s --compressed -o /etc/apt/sources.list.d/cbuild.list "https://cbuild.sourceforge.io/ppa/ubuntu/cbuild.list"
        sudo apt update

Installing package:

sudo apt install libcbuild