There is a Markdown macro @include@. It allows to include one wiki page inside another:

!{{include(Foo)}}

I would like to have similar functionality, but allowing inclusion of repository file. It could be used like this:

!{{include(source:repo_identifier|some/file)}}

This way crucial documentation (README.md, INSTALL.md and so on) can be available both in repository and easily accesible from Redmine Wiki without redundancy (and inconsistencies).

If such feature could go into Redmine core, I'm eager to provide relevant patch.