https://github.com/apache/cloudstack-docs.git is a bit of a dodge-podge of resources
https://github.com/apache/cloudstack-docs-install.git is the install guide
https://github.com/apache/cloudstack-docs-admin.git is the current admin manual.
https://github.com/apache/cloudstack-docs-rn.git is the release notes for individual releases
A plan to consolidate the install and admin guides has been created but not worked on.
https://github.com/apachecloudstack/consolidated-documentation.git is the new consolidated documentation