The manual is provided as Texinfo source (which was originally
derived from the VMS help file in the DECUS TeX distribution of
1990, with many subsequent changes). This is a collaborative
development, and details of getting involved are to be found on
the package home page. All the other formats in the
distribution are derived from the Texinfo source, as usual.

Homepage:
https://ctan.org/pkg/latex2e-help-texinfo
