Examine source code of JIRA2Clipboard

{
  "manifest_version": 2,
  "name": "JIRA2Clipboard",
  "description": "This extension copies the key, summary, generated git-branch name or commit message from an open JIRA issue to the clipboard.",
  "version": "2.3resigned1",
  "browser_action": {
    "default_icon": "JIRA2Clipboard.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "https://tickets.soptim.de/"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{7f7f7812-6547-439b-a522-1114d44b054b}"
    }
  }
}