screenshottag that references a screenshot of your app with elementary OS default settings including the GTK stylesheet, icons, window button position, etc. Screenshots referenced in your MetaInfo should not contain marketing copy, illustrations, or other elements aside from a full-window screenshot of your app in use.
developer_nametag that references your name or the name of your organization.
/usr/share/applications. elementary OS uses a .desktop file to display your app in the applications launcher and the dock. Without this file, your app will not be visible to users.
NoDisplay=trueor anything else that prevents it from showing up in the applications launcher.
/usr/share/icons/hicolorin 32px, 48px, 64px, and 128px. These are the icon sizes that will be displayed in the Applications menu's search, grid, and category views, Multitasking View, the dock, and in AppCenter.