what is .stop in alpine.js code example

Example 1: alpine.js install

<script src="https://cdn.jsdelivr.net/gh/alpinejs/[email protected]/dist/alpine.min.js" defer></script>

Example 2: alpinejs

<div
    x-show="open"
    x-transition:enter="transition ease-out duration-300"
    x-transition:enter-start="opacity-0 transform scale-90"
    x-transition:enter-end="opacity-100 transform scale-100"
    x-transition:leave="transition ease-in duration-300"
    x-transition:leave-start="opacity-100 transform scale-100"
    x-transition:leave-end="opacity-0 transform scale-90"
>...</div>