The composer.json in the 1.29.1 tarball requires "justinrainbow/json-schema": "~3.0", but the tarball contains version 5.2.
This breaks installation of all extensions and skins using composer (even if they don't depend on justinrainbow/json-schema themselves).
(Why the tarball contains require-dev dependencies at all is another question.)
See https://github.com/cmln/chameleon/issues/50 & https://github.com/cmln/chameleon/issues/54