Examine source code of the mirror cracked

{
  "theme": {
    "images": {
      "theme_frame": "The_Lady_of_Shallot_Looking_at_Lancelot.jpg"
    },
    "colors": {
      "frame": "#f2d6b5",
      "tab_background_text": "#004502"
    }
  },
  "version": "2.0",
  "name": "the mirror cracked",
  "manifest_version": 2,
  "description": "Inspired by Waterhouse's illustration for the ballad \"The Lady of Shallot\"."
}