Useful Packages
Below is a list of packages to consider if you need support for a certain task.
Syntax Highlighting
Check out listings and minted. The templates author would slightly recommend to use minted, as listings struggles with UTF-8 encoded files and missing highlighting for some common markups such as YAML. Minted's highlighting is also more semantic, but minted requires pygments, which in turn requires python to be available, and requires passing the --shell-escape or -enable-write18 flag depending on the TeX distribution to the latex compiler.
Drawing UML diagrams
Check out pst-uml, pgf-umlcd and pgf-umlsd. Alternatively use any tool you like and include an image.
Embedding or attaching files
Check out attachfile2, embedfile and navigator.