Examine source code of GetVM: Instant Free Linux

{
  "manifest_version": 2,
  "name": "GetVM: Instant Free Linux",
  "description": "GetVM: Instantly access free Linux, IDEs, and apps from your browser sidebar for coding and learning.",
  "version": "1.6.16",
  "icons": {
    "16": "icon/16.png",
    "48": "icon/48.png",
    "128": "icon/128.png"
  },
  "default_locale": "en",
  "browser_action": {
    "default_title": "Get VM"
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "contextMenus",
    "commands",
    "webRequest",
    "webRequestBlocking",
    "*://getvm.io/*",
    "*://*.getvm.io/*",
    "<all_urls>"
  ],
  "web_accessible_resources": [
    "sidepanel.html",
    "content-scripts/inject-all.css",
    "content-scripts/inject-all.js",
    "content-scripts/inject-frame.js",
    "content-scripts/inject-getvm.js"
  ],
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "windows": "Ctrl+Shift+V",
        "mac": "Command+Shift+V",
        "chromeos": "Ctrl+Shift+V",
        "linux": "Ctrl+Shift+V"
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-scripts/inject-all.js"
      ]
    },
    {
      "matches": [
        "*://*.getvm.io/*"
      ],
      "all_frames": true,
      "run_at": "document_idle",
      "js": [
        "content-scripts/inject-frame.js"
      ]
    },
    {
      "matches": [
        "*://*.getvm.io/*",
        "*://getvm.io/*"
      ],
      "run_at": "document_idle",
      "js": [
        "content-scripts/inject-getvm.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4ab3ca79-e7c5-4d58-bf37-d09335003d44}"
    }
  }
}