Renamed to robinheghan/elm-warrior. It is published under that name, and new versions come out there.
Versions published as Skinney/elm-warrior still install under that name. 15 versions of 15 come from the new location (see their notes).
Rerouted (renamed, verified). The GitHub user or repository was renamed. The tag is still there, at the new name. The Lamdera package server serves a copy recovered from https://github.com/robinheghan/elm-warrior.
What we checked: The repo moved to github.com/robinheghan/elm-warrior. Rebuilt with git archive from commit 4ba4923ae490 of https://github.com/robinheghan/elm-warrior (zip prefix Skinney-elm-warrior-4ba4923/, America/Los_Angeles times): the zip is byte-identical to the one package.elm-lang.org recorded, SHA-1 99be372d532fdd34e34c220fc6284db2fece676e.
The Lamdera compiler uses this copy and prints a one-line notice saying so. elm itself fails to download this version.
Details · package.elm-lang.org's zip: https://github.com/Skinney/elm-warrior/zipball/4.0.1/

This is a game where you hone your Elm skills by programming the AI of a brave warrior, named at, as it navigates mazes and battles dangerous opponents.
You can find the documentation you need to implement your warrior here, but to get started quickly I recommend you clone this repo.
If you complete all the builtin maps you can try to make some of your own, or you can challenge your friends in a warrior deathmatch by cloning this repo and merging in your implementations.
Good luck, you'll need it!