Why 'Red Eclipse' is not into any repo? (It is not into Arch either)

It is a freesoftware game. :/

https://directory.fsf.org/wiki/Red_Eclipse

https://packages.debian.org/source/stretch/redeclipse

https://www.redeclipse.net/docs/FAQ

" Red Eclipse is a Free and Open Source game.

Red Eclipse itself and the Cube Engine 2 are under the zlib License.
    All content in the game is Free, and no more strict than the Creative Commons CC-BY-SA license.
    For more details, see license.txt and trademark.txt. "

Could it be added?