Examine source code of Browserpass

{
  "manifest_version": 3,
  "name": "Browserpass",
  "description": "Browser extension for zx2c4's pass (password manager)",
  "version": "3.12.0",
  "author": "Maxim Baz <browserpass@maximbaz.com>, Steve Gilberd <steve@erayd.net>",
  "homepage_url": "https://github.com/browserpass/browserpass-extension",
  "background": {
    "scripts": [
      "js/background.dist.js"
    ]
  },
  "icons": {
    "16": "icon16.png",
    "128": "icon.png"
  },
  "action": {
    "default_icon": {
      "16": "icon16.png",
      "128": "icon.svg"
    },
    "default_popup": "popup/popup.html"
  },
  "options_ui": {
    "page": "options/options.html",
    "open_in_tab": false
  },
  "permissions": [
    "activeTab",
    "alarms",
    "tabs",
    "clipboardRead",
    "clipboardWrite",
    "nativeMessaging",
    "notifications",
    "scripting",
    "storage",
    "webRequest",
    "webRequestAuthProvider"
  ],
  "host_permissions": [
    "http://*/*",
    "https://*/*"
  ],
  "content_security_policy": {
    "extension_pages": "default-src 'none'; font-src 'self'; img-src 'self' data:; script-src 'self'"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "browserpass@maximbaz.com",
      "strict_min_version": "58.0"
    }
  },
  "commands": {
    "_execute_action": {
      "suggested_key": {
        "default": "Ctrl+Shift+L"
      }
    },
    "fillBest": {
      "suggested_key": {
        "default": "Ctrl+Shift+F"
      },
      "description": "Fill form with the best matching credentials"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "js/early-inject.dist.js"
      ],
      "run_at": "document_start",
      "all_frames": true,
      "world": "MAIN"
    }
  ]
}