Examine source code of blass

{
  "manifest_version": 2,
  "version": "1.13",
  "name": "blass",
  "theme": {
    "colors": {
      "bookmark_text": "rgb(255,255,255)",
      "button_background_active": "rgb(0,0,0)",
      "button_background_hover": "rgb(47,47,47)",
      "frame": "rgb(0,0,0)",
      "frame_inactive": "rgb(0,0,0)",
      "icons": "rgb(255,255,255)",
      "icons_attention": "rgb(255,255,255)",
      "ntp_background": "rgb(0,0,0)",
      "ntp_text": "rgb(255,255,255)",
      "popup": "rgb(0,0,0)",
      "popup_border": "rgb(0,0,0)",
      "popup_highlight": "rgb(47,47,47)",
      "popup_highlight_text": "rgb(255,255,255)",
      "popup_text": "rgb(255,255,255)",
      "sidebar": "rgb(0,0,0)",
      "sidebar_border": "rgb(0,0,0)",
      "sidebar_highlight": "rgb(31,31,31)",
      "sidebar_text": "rgb(255,255,255)",
      "tab_background_separator": "rgb(0,0,0)",
      "tab_background_text": "rgb(131,131,131)",
      "tab_line": "rgb(31,31,31)",
      "tab_loading": "rgb(255,255,255)",
      "tab_selected": "rgb(31,31,31)",
      "tab_text": "rgb(255,255,255)",
      "toolbar": "rgb(0,0,0)",
      "toolbar_top_separator": "rgb(0,0,0)",
      "toolbar_bottom_separator": "rgb(0,0,0)",
      "toolbar_field": "rgb(0,0,0)",
      "toolbar_field_border": "rgb(0,0,0)",
      "toolbar_field_border_focus": "rgb(0,0,0)",
      "toolbar_field_focus": "rgb(0,0,0)",
      "toolbar_field_highlight": "rgb(63,63,63)",
      "toolbar_field_highlight_text": "rgb(255,255,255)",
      "toolbar_field_text": "rgb(255,255,255)",
      "toolbar_field_text_focus": "rgb(255,255,255)",
      "toolbar_field_separator": "rgb(127,127,127)",
      "toolbar_text": "rgb(255,255,255)",
      "toolbar_vertical_separator": "rgb(127,127,127)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "khanchiaseem@outlook.com",
      "strict_min_version": "69.0"
    }
  }
}