One of the new features introduced in a recent monthly update of Oracle Developer Cloud Service is the advanced code search box you can see at the top right when you look at your Git repositories. This is a separate search functionality from the regular project artifacts search the box does in the other section of DevCS.
In the short video below I show you how this works. I start by importing code from a random github project into DevCS - and then I perform a search and show you how to find out the files, lines of code & revision references to your search term. You'll also see how code navigation works in the browser.
For more information about this capability have a look at the documentation here.