Debian
The Debian Project is an association of individuals who have made common cause to create a free operating system. This operating system is called Debian.
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CentOS
CentOS as a group is a community of open source contributors and users which started in 2003 and has been sponsored by Red Hat since 2014. CentOS Linux versions up to CentOS Linux 8 are 100% compatible rebuilds of Red Hat Enterprise Linux, in full compliance with Red Hat's redistribution requirements.