Examine source code of them for work

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "ке4",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(238, 238, 238)",
      "toolbar_text": "rgb(79, 79, 79)",
      "frame": "rgb(238, 238, 238)",
      "tab_background_text": "rgb(94, 94, 94)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(94, 94, 94)",
      "tab_line": "rgb(36, 155, 236)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(79, 79, 79)",
      "button_background_active": "rgb(255, 255, 255)",
      "button_background_hover": "rgb(255, 255, 255)",
      "ntp_background": "rgb(255, 255, 255)",
      "popup_border": "rgb(195, 195, 195)",
      "tab_loading": "rgb(36, 155, 236)",
      "tab_selected": "rgb(255, 255, 255)",
      "tab_text": "rgb(79, 79, 79)",
      "toolbar_field_border": "rgb(255, 255, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{06c3e67b-556d-4775-a28e-75050f764d03}"
    }
  }
}