Optional provides simple, flexible, optional compilation of LaTeX
documents. Option switches may be given via package options, by the
\UseOption command, or interactively via the \AskOption command (help
text may be provided, by defining the \ExplainOptions command). The
package is not robust, in the way that comment package is, against
ill-behaved text. In particular, verbatim text may not be directly
included in optional sections (whether they're included or not). Package
documentation is included in comments within the package itself.

Homepage:
https://www.tug.org/texlive/
