Examine source code of KeepInTab

{
  "manifest_version": 2,
  "name": "KeepInTab",
  "version": "1.0.5",
  "description": "Removes the target attribute (except for named targets) from links, which forces the browser to open every link in the current tab instead of a new tab or window .",
  "icons": {
    "48": "icons/icon.svg",
    "96": "icons/icon.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "keepintab.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f559dab2-2faa-4d8d-9f5f-850f4c937418}"
    }
  }
}