Examine source code of Speechfire

{
  "manifest_version": 2,
  "name": "Speechfire",
  "version": "1.5",
  "description": "Transcribe your speech and paste the result into the focused text field.",
  "permissions": [
    "activeTab",
    "storage",
    "webRequest",
    "webRequestBlocking",
    "*://*/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "icons": {
    "16": "./icon/icon-16.png",
    "48": "./icon/icon-48.png",
    "128": "./icon/icon-128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "./icon/icon-16.png",
      "48": "./icon/icon-48.png",
      "128": "./icon/icon-128.png"
    }
  },
  "commands": {
    "start_stop_transcription": {
      "suggested_key": {
        "default": "Alt+A"
      },
      "description": "Start/Stop transcription"
    }
  },
  "content_security_policy": "script-src 'self'; object-src 'self';",
  "web_accessible_resources": [
    "sounds/start.mp3",
    "sounds/stop.mp3",
    "font/Geist-Medium.otf",
    "font/Geist-Regular.otf",
    "font/Geist-SemiBold.otf"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{ae910057-5295-415b-92c6-1e02c4742165}"
    }
  }
}