GIT sources
The Dolibarr project is developed with PHP and Javascript language (JQuery framework).
Source code of the standard distribution is managed by a GIT server hosted by GitHub and source code for most third parties external modules are hosted on most famous Git services (GitHub, FramaGit, GitLab...)
Some developers or companies hosts their own Git repository.
This is a list of some URL address where you can find the Open source code of Dolibarr project or its addons:
Source code for Dolibarr ERP/CRM
URL for sources: https://github.com/Dolibarr/dolibarr
URL for Doxygen documentation of sources: https://doxygen.dolibarr.org
Source code for external third-parties modules
Most complementary modules sources are provided onto GitHub https://github.com or FramaGit platform : https://git.framasoft.org
Source code Statistics
Some statistics about Dolibarr standard sources are available here : https://www.openhub.net/p/dolibarr/analyses/latest