Examine source code of Adwaita Borderless Light

{
  "name": "Adwaita Borderless White",
  "description": "Unified simple Adwaita Light theme that removes borders, updated for Proton",
  "homepage_url": "https://github.com/Dobbie03/firefox-themes",
  "author": "Dobbie",
  "manifest_version": 2,
  "version": "2.1",
  "icons": {
    "16": "icon-16.png",
    "48": "icon-48.png",
    "96": "icon-96.png",
    "128": "icon-128.png"
  },
  "theme": {
    "colors": {
      "frame": "#DDDAD6",
      "ntp_background": "#E1DEDB",
      "tab_background_separator": "#DDDAD6",
      "tab_background_text": "#111111",
      "tab_selected": "#F0EEEC",
      "toolbar_bottom_separator": "#DDDAD6",
      "toolbar_field_border_focus": "#3584E4",
      "toolbar_field_border": "DDDAD6",
      "popup": "#DCD8D4",
      "popup_border": "#DCD8D4",
      "popup_highlight_text": "#FFFEFE",
      "popup_highlight": "rgba(53, 132, 228, 0.5)",
      "popup_text": "#111111",
      "toolbar_field_separator": "#DDDAD6"
    }
  }
}