what is manifest.json used for code example

Example: manifest.json basic structure

//this is the basic structure of the manifest.json of browser extensions
{
    "name":"demo",
    "version":"1.1",
    "manifest_version":2,

    "description":"a demo extesion for learning purpose",
    "browser_action":{
        "default_title":"a demo title",
        "default_popup":"popup.html"
    },
    "permissions": ["http://*", "https://*" ]
}