gtk:app-chooser-button-append-custom-item (widget name label icon)

widget -- a gtk:app-chooser-button widget
name -- a string with the name of the custom item
label -- a string with the label for the custom item
icon -- a g:icon instance with the icon for the custom item

Appends a custom item to the list of applications that is shown in the popup. The item name must be unique per-widget. Clients can use the provided name as a detail for the "custom-item-activated" signal, to add a callback for the activation of a particular custom item in the list. See also the gtk:app-chooser-button-append-separator function. The gtk:app-chooser-button implementation is deprecated since 4.10.