Examine source code of Papers Please

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Papers Please",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(132, 138, 107)",
      "toolbar_text": "rgb(32, 32, 32)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(97, 83, 82)",
      "toolbar_field": "rgb(210, 229, 245)",
      "toolbar_field_text": "rgb(90, 85, 89)",
      "tab_line": "rgb(162, 148, 144)",
      "popup": "rgb(237, 224, 216)",
      "popup_text": "rgb(87, 72, 72)",
      "button_background_active": "rgba(103, 108, 84, 0.5)",
      "button_background_hover": "rgba(162, 135, 135, 0.57)",
      "frame_inactive": "rgb(97, 83, 82)",
      "icons": "rgb(148, 150, 123)",
      "ntp_background": "rgb(87, 72, 72)",
      "ntp_text": "rgb(87, 72, 72)",
      "popup_border": "rgb(87, 72, 72)",
      "popup_highlight_text": "rgb(144, 155, 162)",
      "popup_highlight": "rgb(194, 205, 212)",
      "sidebar_border": "rgb(66, 42, 28)",
      "sidebar_highlight_text": "rgb(106, 82, 47)",
      "sidebar_highlight": "rgb(66, 42, 28)",
      "sidebar_text": "rgb(66, 42, 28)",
      "sidebar": "rgb(106, 82, 47)",
      "tab_loading": "rgb(207, 153, 121)",
      "tab_text": "rgb(32, 32, 32)",
      "toolbar_field_border_focus": "rgb(224, 233, 199)",
      "toolbar_top_separator": "rgb(137, 106, 103)",
      "toolbar_vertical_separator": "rgb(137, 106, 103)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{72fe53ac-e73b-4a94-91df-89d8f1cb62fa}"
    }
  }
}