Examine source code of Steam Engine by M♥Donna

{
  "name": "Steam Engine by M♥Donna",
  "manifest_version": 2,
  "version": "2.0",
  "theme": {
    "images": {
      "theme_frame": "Steam Engine2 (Custom).jpg"
    },
    "colors": {
      "frame": "rgba(226, 205, 169, 1)",
      "tab_background_text": "rgba(0, 0, 0, 1)",
      "toolbar": "rgba(224, 203, 166, 0)",
      "bookmark_text": "rgba(0, 0, 0, 1)",
      "toolbar_field": "rgba(224, 203, 166, 0.04)",
      "toolbar_field_text": "rgba(0, 0, 0, 1)",
      "tab_line": "rgba(0, 0, 0, 1)"
    }
  }
}