This XWiki Enterprise Manager product has been abandoned in version 5.2 and is not supported anymore. Its main feature was to allow the creation of sub wikis. This multi-wiki feature has been incorporated back into XWiki Enterprise.
For the moment we're keeping this wiki available for our legacy users.
XWiki Enterprise Manager is based on XWiki Enterprise and is now released synchronously with the same version. Hence the roadmap for XWiki Enterprise Manager is now located on the XWiki Enterprise Roadmap.