Examine source code of Side by Side - Split view for Firefox

{
  "manifest_version": 2,
  "name": "Side by Side",
  "version": "2.3.8",
  "description": "Opens two tabs into a split view that can be resized.",
  "permissions": [
    "tabs",
    "activeTab",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>",
    "theme",
    "contextMenus",
    "scripting",
    "management"
  ],
  "icons": {
    "32": "icons/browser-action-icon-gray.svg",
    "48": "icons/browser-action-icon-gray.svg"
  },
  "page_action": {
    "browser_style": true,
    "default_icon": {
      "32": "icons/browser-action-icon-black-32.png",
      "48": "icons/browser-action-icon-black-48.png",
      "64": "icons/browser-action-icon-black-64.png",
      "128": "icons/browser-action-icon-black-128.png"
    },
    "pinned": true,
    "show_matches": [
      "http://*/*",
      "https://*/*"
    ],
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "all_frames": true
    }
  ],
  "web_accessible_resources": [
    "split-view.html",
    "split-view.js"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{19c33907-953f-4b5c-ab9d-829e59bafd93}"
    }
  }
}