I didn’t know Mastodon implemented a built-in way to verify your account, this is great news. For those who want to verify on other networks: you can use keyoxide.org for that - however it is a rather cumbersome process. But I know that the developer (@yarmo) is aware of it and aim to make it more easier to verify different accounts on different platforms.
The Washington Post article linked in “Read More” claims:
Thankfully, this isn’t specific to Mastodon alone — this method is a standard supported by other networks, which means The Post can support verification elsewhere in the future.
However, after a quick Google search, it seems only Mastodon supports this. All results for “fediverse verify” only mention Mastodon.