Knowing the interface of ubuntu and editing them

Well, after some diggin', it's all basically written in C, C++ and Vala.

This link will provide you informations about Unity Development. This one is for Gnome project (Unity is based on Gnome).

You can check the source code of Unity on Launchpad. You can use the source code to edit your interface, it's under GNU GPL v3 licence.

Most of the end-user files are editable with a text-editor (such as gedit, nano), but don't expect much, it isn't as easy to modify as XFCE, for example.

Some strings are stored in dconf, which you can check and modify using dconf-tools or gsettings