The source code of each of the software components is available on their respective sites. For statistics on the source code (and other useful information), please see : Black Duck Open Hub. If you want to use WikiSuite (versus auditing and/or contributing to the source code), please see: How to install WikiSuite
WikiSuite's policy is to work closely with each upstream project to add / improve features there. See also: "Upstream First"
Some quick links to the various repositories:
ClearOS apps created to make it super easy to install, manage and configure the software components
While the apps above where made for WikiSuite, they are designed to make it easy to use any WikiSuite component with ClearOS without necessarily using the whole of WikiSuite.