Examine source code of Marceline Theme-

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "#21171d",
      "tab_background_text": "#ffffff"
    }
  },
  "version": "2.0",
  "name": "Marceline Theme-",
  "manifest_version": 2,
  "description": "█║▌│ █│║▌ ║││█║▌ │║║█║\nαℓgυησѕ Dεяεcнσs яεsεяvαdσs.\nbεnzεmαJFC"
}