Minimalist Countdown Timer

{
    "update_url": "https:\/\/clients2.google.com\/service\/update2\/crx",
    "manifest_version": 3,
    "name": "Minimalist Countdown Timer",
    "version": "1.0",
    "description": "A minimalist countdown timer discreetly tracking time in all your browser tabs in 15 minute intervals.",
    "permissions": [
        "storage"
    ],
    "action": {
        "default_popup": "popup.html",
        "default_icon": {
            "16": "images\/icon16.png",
            "48": "images\/icon48.png",
            "128": "images\/icon128.png"
        }
    },
    "icons": {
        "16": "images\/icon16.png",
        "48": "images\/icon48.png",
        "128": "images\/icon128.png"
    },
    "content_scripts": [
        {
            "matches": [
                "<all_urls>"
            ],
            "js": [
                "contentScript.js"
            ],
            "css": [
                "contentStyles.css"
            ]
        }
    ]
}