claws-mail from home:paulSUSE project

For Debian 11 run the following:

Keep in mind that the owner of the key may distribute updates, packages and repositories that your system will trust (more information).

echo 'deb http://download.opensuse.org/repositories/home:/paulSUSE/Debian_11/ /' | sudo tee /etc/apt/sources.list.d/home:paulSUSE.list
curl -fsSL https://download.opensuse.org/repositories/home:paulSUSE/Debian_11/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/home_paulSUSE.gpg > /dev/null
sudo apt update
sudo apt install claws-mail

For 15.4 run the following as root:

zypper addrepo https://download.opensuse.org/repositories/home:paulSUSE/15.4/home:paulSUSE.repo
zypper refresh
zypper install claws-mail

For xUbuntu 20.04 run the following:

Keep in mind that the owner of the key may distribute updates, packages and repositories that your system will trust (more information).

echo 'deb http://download.opensuse.org/repositories/home:/paulSUSE/xUbuntu_20.04/ /' | sudo tee /etc/apt/sources.list.d/home:paulSUSE.list
curl -fsSL https://download.opensuse.org/repositories/home:paulSUSE/xUbuntu_20.04/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/home_paulSUSE.gpg > /dev/null
sudo apt update
sudo apt install claws-mail