See texdoc's web page for general information about Texdoc, including its documentation and how to run the development version.
doc/documentation;texdoc.cnfdefault configuration file;script/*.tluTexdoc's code;script/*.luadistributed data files, generated withtools/gen-datafiles;tools/helper scripts for maintainance and/or testing; some of them might run poperly only on my (mpg) machine.