Linux Mint's purpose is to produce a modern, elegant and comfortable operating system which is both powerful and easy to use.
Linux Mint is one of the most popular desktop Linux distributions and used by millions of people.
This beta release is for codename Elsie / LMDE5, that is Linux Mint Debian Edition, since it derives from Debian solely rather than through Ubuntu. LMDE project development helps gauge the strain of cutting ties with Ubuntu / Canonical, should that become a more compelling direction for the Mint community.
Release notes are at https://linuxmint.com/rel_elsie.php