unouter – Suppress \outer flags in Plain TeX
The package suppresses all the \outer flags on macros in Plain TeX; it also suppresses the \outer command.
Free license not otherwise listed, or more than one free license applies
support for development of (La)TeX macros
Maybe you are interested in the following packages as well.
- redefine: Conditional macro, etc., definitions
- bibplain: Simple macros for using BibTeX with Plain TeX
- nextpage: Generalisations of the page advance commands
- balancedquotes: Code balanced quotes according to document language