Examine source code of Aero Blue & Gray

{
  "theme": {
    "images": {
      "theme_frame": "header.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000"
    }
  },
  "version": "2.0",
  "name": "Aero Blue & Gray",
  "manifest_version": 2,
  "description": "A blue title bar similar in shade to Windows' Aero blue, and a light gray status bar for Thunderbird."
}