Examine source code of Solo Leveling theme

{
  "name": "Solo Leveling",
  "manifest_version": 2,
  "version": "1.0",
  "browser_specific_settings": {
    "gecko": {
      "id": "mk3606@gmail.com"
    }
  },
  "theme": {
    "images": {
      "theme_frame": "images/Solo Leveling Theme [Firefox] 1919x211.jpg"
    },
    "colors": {
      "frame": "black",
      "tab_background_text": "#fff",
      "bookmark_text": "rgba(0,0,0,1)",
      "toolbar_field_text": "rgba(43,53,61,1)",
      "tab_text": "white",
      "toolbar": "rgba(0,0,0,.5)",
      "toolbar_text": "white",
      "button_background_active": "red",
      "button_background_hover": "red"
    }
  }
}