Examine source code of FeedMe

{
    "author": "Wes Johnston",
    "background": {
        "page": "background.html",
        "persistent": true
    },
    "content_scripts": [
        {
            "matches": [
                "<all_urls>"
            ],
            "js": [
                "borderify.js"
            ]
        }
    ],
    "description": "A little rss feed reader for Firefox",
    "icons": {
        "48": "icons/Subscribe.svg"
    },
    "manifest_version": 2,
    "name": "Feed Sidebar",
    "options_ui": {
        "page": "options/options.html",
        "browser_style": true,
        "chrome_style": true
    },
    "page_action": {
        // "browser_style": true,
        "default_icon": {
            "19": "icons/Subscribe.svg",
            "38": "icons/Subscribe.svg"
        },
        "default_title": "Subscribe"
    },
    "permissions": [
        "<all_urls>",
        "storage",
        "tabs",
        "bookmarks",
        "history"
    ],
    "sidebar_action": {
        "default_title": "Feeds",
        "default_panel": "sidebar/sidebar.html",
        "default_icon": "icons/Subscribe.svg"
    },
    "version": "0.1.1"
}