Renamed to staeter/ziplist. It is published under that name, and new versions come out there.
Versions published as STTR13/ziplist still install under that name. 3 versions of 7 come from the new location (see their notes). 4 versions could not be recovered and cannot be installed.
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/staeter/ziplist.
What we checked: The repo moved to github.com/staeter/ziplist. Rebuilt with git archive from commit fafa01e9632c of https://github.com/staeter/ziplist (zip prefix STTR13-ziplist-fafa01e/, America/Los_Angeles times): the zip is byte-identical to the one package.elm-lang.org recorded, SHA-1 24b0aebef8a5f37efbe656325a84a7e079808e98.
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/STTR13/ziplist/zipball/1.0.0/
This package is inspired by guid75/ziplist and Richard Feldman's conference Making Impossible States Impossible.
A ZipList is a list that has an element selected that can go through the whole list and act on it.