Examine source code of Journal Save Button

{
  "background": {
    "page": "background.html"
  },
  "browser_action": {
    "default_title": "Save to Journal"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "journalextension-sansnt@usejournal.com",
      "strict_min_version": "70.0"
    }
  },
  "commands": {
    "add-to-journal": {
      "description": "Save to Journal",
      "suggested_key": {
        "default": "Alt+Shift+J",
        "mac": "Command+Shift+J"
      }
    }
  },
  "content_security_policy": "script-src 'self';style-src * 'unsafe-inline';connect-src https://*.canopyiq.com wss://*.canopyiq.com https://*.usejournal.com wss://*.usejournal.com https://*.launchdarkly.com https://*.auth0.com https://*.canopyiq.com https://api.segment.io https://*.ingest.sentry.io ws://127.0.0.1:61803 http://127.0.0.1:61803;media-src;child-src https://www.youtube.com https://player.vimeo.com https://fast.wistia.net;default-src 'self';font-src 'self' https://* data:;img-src 'self' https://* http://* data:",
  "description": "Save links, documents, and more to Journal.",
  "icons": {
    "16": "img/icon16.png",
    "32": "img/icon32.png",
    "48": "img/icon48.png",
    "128": "img/icon128.png"
  },
  "manifest_version": 2,
  "name": "Journal Save Button",
  "omnibox": {
    "keyword": "j"
  },
  "options_ui": {
    "open_in_tab": false,
    "page": "options.html"
  },
  "permissions": [
    "webRequest",
    "contextMenus",
    "tabs",
    "storage",
    "cookies",
    "unlimitedStorage",
    "https://*/*",
    "http://*/*"
  ],
  "version": "2020.47",
  "web_accessible_resources": [
    "css/*",
    "img/*",
    "inject.html",
    "test.gif"
  ]
}