Gtk.TextIter.prototype.get_marks

function get_marks():[Gtk.TextMark] {
    // Gjs wrapper for gtk_text_iter_get_marks()
}

Returns a list of all Gtk.TextMark at this location. Because marks are not iterable (they don't take up any "space" in the buffer, they are just marks in between iterable locations), multiple marks can exist in the same place. The returned list is not in any meaningful order.