Description

Hi,
I am trying to put the source code for FontAwesome v6 in Header section in AMP:
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.3.0/css/all.min.css">

The problem is that Google Search Console for AMP claims this is incorrect and I get error: 'The 'href' attribute in the 'link rel=stylesheet for fonts' tag is set to an invalid value 'https://cdnjs.cloudflare.com/ajax/libs/fon...'

Therefore, I can see Font Awesome icons, but I am not fine with Google AMP standards.

I also tried to put in Header of AMP page below style amp-custom, but then I do not see the icons.

<style amp-custom>
@font-face {
font-family: "Font Awesome 6 Free";
src: url(https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.3.0/css/all.min.css);}
body { font-family: "Font Awesome 6 Free";content="";}
</style>

Can you tell me if this is a bug on your side or if maybe I should correct something?

Thanks for your help.
Jakub

Reproduction Steps

1. Put in the Header section of AMP page below code:
   <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.3.0/css/all.min.css">
2. Google Search Console throws error: 'The 'href' attribute in the 'link rel=stylesheet for fonts' tag is set to an invalid value 'https://cdnjs.cloudflare.com/ajax/libs/fon...'

Relevant Logs

No response

Browser(s) Affected

Chrome, Firefox

OS(s) Affected

No response

Device(s) Affected

No response

AMP Version Affected

No response