Fediverse creator meta tag

The fedivers:creator meta tag was announced on the Mastodon Notion site on May 22 and released on July 2 on their blog with slightly different formats:

Notion: <meta property="fediverse:creator" content="username@domain" />
Blog: <meta name="fediverse:creator" content="@Gargron@mastodon.social" />

but because the blog is about the actual implementation, let’s assume that one is the correct format.

There is another thing that bugs me: The HTML Tag clearly states that there isn’t a slash at the end: > instead of />. The W3C Markup Validation Service doesn’t mark this as an error but warns about it:

Trailing slash on void elements has no effect and interacts badly with unquoted attribute values

Seems to me that if you’re building websites for a living, you keep a close look on the specifications and follow them as closely as you can.
But apparently not ¯\_(ツ)_/¯.