Gutter icons are located in the editor on the left. They invoke some basic actions and other framework- and technology-specific features.
Use the Gutter Icons page in Settings/Preferences to hide or show icons in the gutter.
Note that technology-related icons are displayed only if the corresponding plugin is installed and enabled. Refer to Manage plugins for more information on how to install plugins.
To display or hide an icon in the gutter, select or clear the checkbox next to it. If you want to disable all gutter icons, clear the Show gutter icons checkbox above the list of available icons.