packagecloud.io/crowdsec (Crowdsec Security)

apt update
apt install debian-archive-keyring
apt install -y curl gnupg apt-transport-https
mkdir -p /etc/apt/keyrings/
curl -fsSL https://packagecloud.io/crowdsec/crowdsec/gpgkey | gpg --dearmor > /etc/apt/keyrings/crowdsec_crowdsec-archive-keyring.gpg
echo "deb [signed-by=/etc/apt/keyrings/crowdsec_crowdsec-archive-keyring.gpg] https://packagecloud.io/crowdsec/crowdsec/any any main" > /etc/apt/sources.list.d/crowdsec_crowdsec.list
echo "#deb-src [signed-by=/etc/apt/keyrings/crowdsec_crowdsec-archive-keyring.gpg] https://packagecloud.io/crowdsec/crowdsec/any any main" >> /etc/apt/sources.list.d/crowdsec_crowdsec.list
apt update
apt install crowdsec

from https://docs.crowdsec.net/u/getting_started/installation/linux/