Examine source code of Killer Red

{
  "name": "Killer",
  "manifest_version": 2,
  "version": "2.0",
  "description": "Killer UI Atom theme ported to Firefox",
  "theme": {
    "images": {
      "theme_frame": "./transparent.png"
    },
    "colors": {
      "tab_selected": "#181717",
      "tab_text": "#c9c3c5",
      "toolbar": "#181717",
      "tab_background_separator": "#ad2419",
      "sidebar": "#181717",
      "sidebar_border": "#181717",
      "sidebar_text": "#c9c3c5",
      "tab_line": "#181717",
      "toolbar_field": "#302e2e",
      "toolbar_field_text": "#c9c3c5",
      "toolbar_field_border": "#181717",
      "toolbar_field_separator": "#155c5e",
      "icons": "#b1b0b0",
      "icons_attention": "#e3a01a",
      "popup": "#201e1e",
      "popup_highlight": "#0d0c0c",
      "popup_text": "#c9c3c5",
      "toolbar_bottom_separator": "#181717",
      "toolbar_field_border_focus": "#155c5e",
      "toolbar_top_separator": "#201e1e",
      "tab_loading": "#155c5e",
      "button_background_hover": "#0d0c0c",
      "ntp_background": "#181717",
      "ntp_text": "#c9c3c5",
      "frame": "#ad2419",
      "tab_background_text": "#ffffff",
      "bookmark_text": "#c9c3c5"
    }
  }
}