Examine source code of vimminkeys

{
  "manifest_version": 2,
  "name": "vimminkeys",
  "description": "Minimal Vim directional keybindings for Firefox.",
  "author": "Erin Burton",
  "version": "0.0.2",
  "applications": {
    "gecko": {
      "id": "ebflat9@vimminkeys.id"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "run_at": "document_start",
      "match_about_blank": true
    }
  ]
}