LaTeX_ packages being developed start in this incubator until they reach sufficient maturity for a stable API.
Pakin, "How to Package Your LaTeX Package_," September 2015
The LaTeX Project, "LaTeX2e for class and package writers_," February 2006
.. External Hyperlink Targets (sorted order)
.. _How to Package Your LaTeX Package: http://mirrors.ctan.org/info/dtxtut/dtxtut.pdf
.. _LaTeX: https://www.latex-project.org/
.. _LaTeX2e for class and package writers: https://www.latex-project.org/help/documentation/clsguide.pdf