Hey there, Takahiro Saito
When I click onto the link in the article, it takes me to a page titled 'We're sorry, the page you requested cannot be found!'
This means that it may not be available. It does, however, provide me with an email address you can use to contact the Visual Studios Marketplace team. The email is: vsmarketplace @microsoft.com
You can click onto the link when you visit this page: https://marketplace.visualstudio.com/items?itemName=ms-dotnettools.appcat
Hope this helps,
Nathan