In the docs under tutorials there is the subsection particles and a subsubsection called ''Simulating Particles with LIGGGHTS'' where a repository link is broken.
The link to clone the repository
git clone https://github.com/CFDEMproject/LPP.git
yields
Cloning into 'LPP'...
info: please complete authentication in your browser...
remote: Repository not found.
fatal: repository 'https://github.com/CFDEMproject/LPP.git/' not found