Renamed to elm-messenger/messenger-core. That is where the repository lives now. It has not been published as a package under the new name.
Versions published as linsyking/messenger-core still install under that name. 34 versions of 52 come from the new location (see their notes). 7 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/elm-messenger/messenger-core.
What we checked: The repo moved to github.com/elm-messenger/messenger-core. Rebuilt with git archive from commit c293eb1bf238 of https://github.com/elm-messenger/messenger-core (zip prefix linsyking-messenger-core-c270288/, America/Los_Angeles times): the zip is byte-identical to the one package.elm-lang.org recorded, SHA-1 7b945f71026ab90e76c8bd8c4487cdeff913b9f5.
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/linsyking/messenger-core/zipball/10.0.0/
Single Transition
Generate new transition
Null Transition
Transition has two stages:
From the old scene to the transition scene
From the transition scene to the new scene