Examine source code of Future-Tab

{
  "manifest_version": 2,
  "name": "future-tab",
  "version": "2.6.19",
  "icons": {
    "16": "icon-16.png",
    "32": "icon-32.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "downloads",
    "history",
    "bookmarks",
    "search",
    "scripting",
    "userScripts",
    "contextMenus",
    "management",
    "tabGroups",
    "identity",
    "https://*/*",
    "http://*/*"
  ],
  "omnibox": {
    "keyword": "ft"
  },
  "commands": {
    "open-side-panel": {
      "suggested_key": {
        "default": "Ctrl+Shift+E",
        "mac": "Command+Shift+E"
      },
      "description": "Open the side panel"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "future-tab-remake@example.com",
      "strict_min_version": "115.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  },
  "browser_action": {
    "default_title": "Future Tab",
    "default_popup": "popup.html"
  },
  "devtools_page": "devtools.html",
  "options_ui": {
    "open_in_tab": true,
    "page": "options.html"
  },
  "sidebar_action": {
    "default_panel": "sidepanel.html",
    "default_title": "Future Tab - Side Panel"
  },
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "run_at": "document_start",
      "js": [
        "content-scripts/content.js"
      ]
    }
  ]
}