Where can I find all details, references and the background for this component-based metadata concept?

Check out the CLARIN specification document: http://www.clarin.eu/files/wg2-4-metadata-doc-v5.pdf

PLEASE NOTE: the information in this document might be partially outdated, http://www.clarin.eu/cmdi (including these FAQs) is certainly more up to date and should be considered authorative.