expl3 (LaTeX3) Development Repository
The repository contains development material for
expl3. This includes
not only code to be developed into the
expl3 kernel, but also a variety
of test, documentation and more experimental material. All of this code works
on top of LaTeX2e.
The following directories are present in the repository:
l3kernel: code forms the
expl3kernel and with the exception of the contents of
l3candidates, all stable code. With a modern LaTeX2e kernel, this code is loaded during format creation; when using an older LaTeX2e kernel, this material is accessible using the
l3backend: code for backend (driver) level interfaces across the
expl3codebase; none of this code has public interfaces, and so no distinction is made between stable and experimental code.
l3packages: code which is written to be used on top of LaTeX2e to explore interfaces; these higher-level packages are 'stable'. It is unlikely that any new packages will be added to this area.
l3experimental: code which is written to be used on top of LaTeX2e to experiment with code and interface concepts. The interfaces for these packages are still under active discussion. Parts of this code may eventually be migrated to
l3trial: material which is under very active development, for potential addition to
l3experimental. Material in this directory may include potential replacements for existing modules, where large-scale changes are under-way. This code is not released to CTAN.
l3leftovers: code which has been developed in the past by The LaTeX 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
Support material for development is found in:
support, which contains files for the automated test suite which are 'local' to the repository.
Documentation is found in:
articles: discussion of 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.
Discussion concerning the approach, suggestions for improvements, changes, additions, etc. should be addressed to the list LaTeX-L.
You can subscribe to this list by sending mail to
with the body containing
subscribe LATEX-L <Your-First-Name> <Your-Second-Name>
The issue tracker for
expl3 is currently located
Please report specific issues with
expl3 code there; more general
discussion should be directed to the LaTeX-L list.
We use GitHub Actions as a hosted continuous integration service. For each commit, the build status is tested using the current release of TeX Live.
This code is developed by The LaTeX Project.
This README file is copyright 2021,2022 The LaTeX Project.