The documentation analysis report generation is split into two processes:
Collect data and save it
Generate different reports from saved data
generateCoverage() in QA_Peardoc_Coverage generates and returns the array with the computed coverage data. It can be serialized and saved, since all the Renderer classes use it as input.
Classes implementing the QA_Peardoc_Coverage_Renderer interface provide a render() method that takes the data returned by generateCoverage() and return the analysis, most times a string containing HTML code.