Examine source code of ExtractNews

{
  "name": "__MSG_extensionName__",
  "description": "__MSG_extensionDescription__",
  "author": "Yoshinori Kawagita",
  "version": "1.1.2",
  "homepage_url": "https://github.com/kawagita/ExtractNews/",
  "manifest_version": 2,
  "default_locale": "en",
  "icons": {
    "16": "icons/extractnews-16.png",
    "48": "icons/extractnews-48.png",
    "96": "icons/extractnews-96.png"
  },
  "permissions": [
    "activeTab",
    "alarms",
    "contextMenus",
    "storage",
    "tabs"
  ],
  "background": {
    "scripts": [
      "debug.js",
      "extractnews.js",
      "storage.js",
      "text.js",
      "alert.js",
      "popup/popup.js",
      "tab_setting.js",
      "context_menu.js",
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.yahoo.com/*",
        "https://news.yahoo.com/*",
        "https://finance.yahoo.com/*",
        "https://money.yahoo.com/*",
        "https://sports.yahoo.com/*"
      ],
      "js": [
        "debug.js",
        "extractnews.js",
        "site/site.js",
        "site/urlparser.js",
        "site/selector.js",
        "site/design.js",
        "site/yahoo.js"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "https://*.slashdot.org/*",
        "https://slashdot.org/*",
        "https://*.srad.jp/*",
        "https://srad.jp/*"
      ],
      "js": [
        "debug.js",
        "extractnews.js",
        "site/site.js",
        "site/urlparser.js",
        "site/selector.js",
        "site/design.js",
        "site/slashdot.js"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "https://news.yahoo.co.jp/*"
      ],
      "js": [
        "debug.js",
        "extractnews.js",
        "site/site.js",
        "site/urlparser.js",
        "site/selector.js",
        "site/design.js",
        "site/yahoo_japan.js"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "https://*.watch.impress.co.jp/*"
      ],
      "js": [
        "debug.js",
        "extractnews.js",
        "site/site.js",
        "site/urlparser.js",
        "site/selector.js",
        "site/design.js",
        "site/impress_watch.js"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "https://www.itmedia.co.jp/news/*"
      ],
      "js": [
        "debug.js",
        "extractnews.js",
        "site/site.js",
        "site/urlparser.js",
        "site/selector.js",
        "site/design.js",
        "site/itmedia.js"
      ],
      "run_at": "document_start"
    },
    {
      "matches": [
        "<all_urls>"
      ],
      "exclude_matches": [
        "https://www.yahoo.com/*",
        "https://news.yahoo.com/*",
        "https://finance.yahoo.com/*",
        "https://money.yahoo.com/*",
        "https://sports.yahoo.com/*",
        "https://*.slashdot.org/*",
        "https://slashdot.org/*",
        "https://*.srad.jp/*",
        "https://srad.jp/*",
        "https://news.yahoo.co.jp/*",
        "https://*.watch.impress.co.jp/*",
        "https://www.itmedia.co.jp/news/*"
      ],
      "js": [
        "debug.js",
        "extractnews.js",
        "site/site.js",
        "site/urlparser.js",
        "site/selector.js",
        "site/others.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "19": "icons/flag-19.png",
      "38": "icons/flag-38.png"
    },
    "default_popup": "popup/list.html",
    "default_title": "__MSG_browserActionShowNewsSelections__"
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": true
  }
}