Change Messenger's Theme

{
    "update_url": "https:\/\/clients2.google.com\/service\/update2\/crx",
    "manifest_version": 2,
    "name": "Change Messenger's Theme",
    "version": "2.1.3",
    "description": "A small tool changing the messenger's background",
    "icons": {
        "16": "icon.png",
        "48": "icon.png",
        "128": "icon.png"
    },
    "browser_action": {
        "default_icon": {
            "16": "icon.png",
            "48": "icon.png",
            "32": "icon.png"
        },
        "default_title": "Messenger's Background tool",
        "default_popup": "index.html"
    },
    "author": "Nghiacangao_btteam",
    "background": {
        "scripts": [
            "\/js\/core.js",
            "background.js"
        ],
        "persistent": false
    },
    "content_scripts": [
        {
            "matches": [
                "https:\/\/www.messenger.com\/t\/*",
                "https:\/\/www.facebook.com\/messages\/t\/*"
            ],
            "js": [
                "content.js",
                "\/js\/core.js"
            ],
            "css": [
                "\/css\/contentCss\/contentCss.css"
            ],
            "all_frames": true
        }
    ],
    "permissions": [
        "tabs",
        "storage",
        "contextMenus",
        "notifications"
    ]
}