OpenGeo Explorer
This plugin for QGIS has been discontinued.
GeoServer functionality can now be found in the GeoServer plugin
https://github.com/boundlessgeo/qgis-geoserver-plugin
PostGIS functionality is available in the built-in QGIS DB Manager
Documentation
Nevertheless, the plugin is documented here.
Cloning this repository
This repository uses external repositories as submodules. Therefore in order to include the external repositories during cloning you should use the --recursive option:
git clone --recursive http://github.com/boundlessgeo/qgis-suite-plugin.git
Also, to update the submodules whenever there are changes in the remote repositories one should do:
git submodule update --remote