GIT Sources
The Dolibarr project is developed with PHP and the Javascript (jQuery framework) languages.
Source code of the standard distribution is managed by a GIT server hosted by GitHub and source code for most external / third party modules are hosted on renowned Git services (GitHub, FramaGit, GitLab etc.)
Some developers or companies host their own Git repository.
You will find below, a list of URLs where you can find the Open source code of the Dolibarr project and 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 of the sources of complementary modules are available on GitHub https://github.com or the FramaGit platform: https://git.framasoft.org
Source code Statistics
Some statistics about Dolibarr's standard sources are available here: https://www.openhub.net/p/dolibarr/analyses/latest