Examine source code of Easy On Eyes

{
  "manifest_version": 2,
  "version": "1.3",
  "name": "Easy On Eyes",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(239, 239, 239)",
      "toolbar_text": "rgb(45, 45, 45)",
      "frame": "rgb(45, 45, 45)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(239, 239, 239)",
      "popup": "rgb(239, 239, 239)",
      "popup_text": "rgb(0, 0, 0)",
      "tab_loading": "rgb(239, 239, 239)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{44afd153-9aa1-4bcb-8206-6c4b8d4f466c}"
    }
  }
}