Examine source code of First Party Isolation

{
  "description": "__MSG_extensionDescription__",
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "1.4.0",
  "homepage_url": "https://github.com/mozfreddyb/webext-firstpartyisolation",
  "default_locale": "en",
  "icons": {
    "48": "icons/fishbowl.svg",
    "96": "icons/fishbowl.svg"
  },
  "permissions": [
    "privacy"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/fishbowl-light.svg",
      "32": "icons/fishbowl-light.svg"
    },
    "theme_icons": [
      {
        "light": "icons/fishbowl-light.svg",
        "dark": "icons/fishbowl-light.svg",
        "size": 32
      }
    ],
    "default_title": "Click to disable First Party Isolation"
  },
  "applications": {
    "gecko": {
      "strict_min_version": "58.0a1"
    }
  }
}