The extension hides and show elements in websites through IDs and Classes. You can type the name of the element or use the picker tool. There's a class/id toggle button which you can change between both while typing the name, or it will be automatically selected when pasting or using the picker. The elements of each site are displayed inside individual folders for each site. There's a button for persistence, so when you close the browser, elements will continue there, being hidden automatically without the need for you to hide it again.
