diff --git a/docs/api/app.md b/docs/api/app.md
index b35c4c7259..5d76e8ed92 100644
--- a/docs/api/app.md
+++ b/docs/api/app.md
@@ -1222,7 +1222,7 @@ Show the app's about panel options. These options can be overridden with `app.se
   * `credits` String (optional) _macOS_ _Windows_ - Credit information.
   * `authors` String[] (optional) _Linux_ - List of app authors.
   * `website` String (optional) _Linux_ - The app's website.
-  * `iconPath` String (optional) _Linux_ _Windows_ - Path to the app's icon. On Linux, will be shown as 64x64 pixels while retaining aspect ratio.
+  * `iconPath` String (optional) _Linux_ _Windows_ - Path to the app's icon in a JPEG or PNG file format. On Linux, will be shown as 64x64 pixels while retaining aspect ratio.
 
 Set the about panel options. This will override the values defined in the app's `.plist` file on macOS. See the [Apple docs][about-panel-options] for more details. On Linux, values must be set in order to be shown; there are no defaults.