The last three parts are probably a date in yy.m.d format. Package names only get longer as you add more layers of maintainers. (For example, package-XubuntuY

The last three parts are probably a date in yy.m.d format. Package names only get longer as you add more layers of maintainers. (For example, package-XubuntuY or package+YYYYmmdd-n was common on Ubuntu, who needed their versions to fit "between" given Debian versions.)