Where is the source code html of Wordpress editor?

Realizovy the simple engine and the only thing missing is a simple html editor like in wordpress. It html-tion, rather than visual:


Maybe someone of you knows where to look for its source code files of the engine? What the editors have not tried to put it all visual, and usually with a bunch of unnecessary to me if the source code to see if I can get any chance for their engine editor to move...