@umemu I can't find the post from your screenshot but I found a similar one: https://mastodon.social/@fedidb/117459876390864809

The second link is displayed because it is "attached" to the ActivityPub object:

"attachment": [
{
"href": "https://fedidb.com/software/compare?software=mastodon,gotosocial,hometown,misskey",
"type": "Link"
}
],

Mitra appends attached links to posts because Lemmy does this. It seems that Mastodon does this too, for different reasons. I'll see what we can do about it.