Yet another separated tool. The Elasticsearch ecosystem is not going to became simpler with ES 5 removing the "site" plugins and everyone doing their own apps instead of building Kibana Apps (i.e. Cerebro, the new Kopf)...
Links:
[1] Hosted app - http://appbaseio.github.io/mirage/
[2] Chrome extension - https://chrome.google.com/webstore/detail/mirage/dcnlpfmnpog...
[3] Site Plugin for Elasticsearch v2.x - plugin install appbaseio/mirage
It's always been a good idea to deploy them in that way - no need to have the plugin on each node, easier version upgrades, access to multiple clusters etc. So basically, not much changed.