The repository contains development material for LaTeX3. This includes not only code to be developed into the LaTeX3 kernel, but also a variety of test, documentation and more experimental material. A great deal of the experimental LaTeX3 code can be loaded within LaTeX2e to allow development and testing to occur.
The following directories contain experimental LaTeX3 code:
l3kernel: code which is intended to eventually appear in a stand-alone LaTeX3 format. Most of this material is also usable on top of LaTeX2e when loading the expl3 package.
l3backend: code for backend (driver) level interaces across the expl3 codebase.
l3packages: code which is written to be used on top of LaTeX2e to experiment with LaTeX3 concepts. The interfaces to these higher-level packages are 'stable'.
l3experimental: code which is written to be used on top of LaTeX2e to experiment with LaTeX3 concepts. The interfaces for these packages are still under active discussion. Parts of this code may eventually be migrated to l3kernel, while other parts are tied closely to LaTeX2e and are intended to support mixing LaTeX2e and LaTeX3 concepts.
l3trial: material which is under very active development, for potential addition to l3kernel or l3experimental. Material in this directory may include potential replacements for existing modules, where large-scale changes are under-way.
l3leftovers: code which has been developed in the past by The LaTeX3 Project but is not suitable for use in its current form. Parts of this code may be used as the basis for new developments in l3kernel or l3experimental over time.
Support material for development is found in:
support, which contains files for the automated test suite which are 'local' to the LaTeX3 repository.
Documentation is found in:
articles: discussion of LaTeX3 concepts by team members for publication in TUGBoat or elsewhere.
The repository also contains the directory xpackages. This contain code which is being moved (broadly) l3experimental. Over time, xpackages is expected to be removed from the repository. The directory contrib is used to test the interaction of LaTeX3 code with selected contributed packages.