Emmet is a system that allows coder to write shorthand and have it expanded when you push the tab key. It can save a lot of typing when writing web pages. Eg. you type p the tab and you get <p></p>, or you type div.wrapper and tab you get <div class="wrapper"></div> You can even do more advanced things like creating multiple instances with nested objects. Here is an example of Emmet implemented in Ace https://ace.c9.io/demo/emmet.html Go ahead and type p +tab on an empty line or ul>(li.item>a)*5 plus tab. Here is the documentation for Emmet https://docs.emmet.io/abbreviations/syntax/