Examine source code of SPC

{
  "manifest_version": 2,
  "name": "SPC",
  "description": "Inserting special characters made easy.",
  "version": "1.0.1",
  "homepage_url": "https://github.com/khang-nd/spc",
  "permissions": [
    "contextMenus",
    "activeTab"
  ],
  "icons": {
    "48": "icon.png"
  },
  "background": {
    "scripts": [
      "build/background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "build/main.css.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "build/main.css"
  ],
  "commands": {
    "open_popup": {
      "description": "Activate the extension",
      "suggested_key": {
        "default": "Alt+Period"
      }
    }
  }
}