The files in the repository are created by LibreOffice or OpenOffice which are free open source softwares.
Although they are text based, comparing them in Github is not useful.
Use LibreOffice or OpenOffice “Compare Document” feature to compare two versions of a document.
Open the newer version of your document and then choose menu items Edit/Track Changes/Compare Document.
0000summary.pdf gives an overview of the contents of the repository.
Aik-Siong Koh