In the world of HTML, a CSS selector is a piece of code used to select an HTML element that you want to style with CSS. This is done by combining a variety of attributes, like a class or id, to find an element that matches your criteria. But this selector can be generated from a number of different samples in order to find the elements you want to style and design them in the most efficient way.

It is a very important piece of knowledge for anyone working with HTML, and this is why this extension is made available as an educational tool.

It is a very good idea to create a selector and style an element in the developer tools in order to see how the selectors are generated. This is done by pressing the "Enable Selection Mode" option.