Это старая версия документа!
echo 'deb http://download.opensuse.org/repositories/home:/hpcoder1/xUbuntu_20.04/ /' | sudo tee /etc/apt/sources.list.d/home:hpcoder1.list
curl -fsSL https://download.opensuse.org/repositories/home:hpcoder1/xUbuntu_20.04/Release.key | gpg –dearmor | sudo tee /etc/apt/trusted.gpg.d/home:hpcoder1.gpg > /dev/null
sudo apt install scidavis