Examine source code of Mezmer Browser Extension

{
  "manifest_version": 2,
  "name": "Mezmer",
  "description": "Save images from the web to your Mezmer library.",
  "version": "1.2.5",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "128": "icons/icon128.png"
  },
  "browser_action": {
    "default_title": "Save to Mezmer",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png"
    }
  },
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "api.js",
      "background.js"
    ]
  },
  "commands": {
    "batch-save": {
      "suggested_key": {
        "default": "Alt+1"
      },
      "description": "Batch save images"
    },
    "capture-area": {
      "suggested_key": {
        "default": "Alt+2"
      },
      "description": "Capture area"
    },
    "capture-visible": {
      "suggested_key": {
        "default": "Alt+3"
      },
      "description": "Capture visible area"
    },
    "capture-page": {
      "description": "Capture full page"
    }
  },
  "permissions": [
    "contextMenus",
    "storage",
    "activeTab",
    "notifications",
    "tabs",
    "webNavigation",
    "http://127.0.0.1:47832/*",
    "http://localhost:47832/*",
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "js": [
        "browser-polyfill.js",
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "mezmer@extension.local",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}