This plugin adds a new button to the wiki editor. When clicked, a popup dialog with the directory structure of the projects repository is shown and can be browsed. Once you found the file you where looking for, a link (export:"path/filename") is added into the editor textform.
Change to redmine/plugins folder and run:
git clone https://github.com/tleish/redmine_jstoolbar_ext
git clone https://github.com/gilbertf/redmine_repobrowser.git