Yes, but if you look at the page source you will see that they have all been converted to PNG even though it shows Webp here.
<link rel="icon" sizes="36x36" href="//media.invisioncic.com/a319035/monthly_2021_11/android-chrome-36x36.png?v=1709133612">
<link rel="icon" sizes="48x48" href="//media.invisioncic.com/a319035/monthly_2021_11/android-chrome-48x48.png?v=1709133612">
<link rel="icon" sizes="72x72" href="//media.invisioncic.com/a319035/monthly_2021_11/android-chrome-72x72.png?v=1709133612">
The problem here is that when you send an icon in webP, it only has the name changed from webP to PNG, but the encoding remains unchanged.
When you try to open the file, for example in Photoshop, an error is displayed that this file is not PNG, even though it is in this format.
As you can see, even though the file has been changed to PNG, it still has the encoding from the original file, i.e. WebP.
WEBPVP8