I'm on one Matrix channel where an instance of this bot is posting updates from Mastodon. My home server doesn't have URL previews enabled. As a result the bot's messages show up like this (screenshot from Nheko; Element is very similar):

Looking at the raw event, I can see that it has an URL, but the <a> tag in the formatted body does not have any text content:
"content": {
"body": "Skrolli-lehti: ( https://some.skrolli.fi/@skrollilehti/109563577778791522 )",
"format": "org.matrix.custom.html",
"formatted_body": "<strong>Skrolli-lehti</strong>:<br><a href=\"https://some.skrolli.fi/@skrollilehti/109563577778791522\"><strong></strong></a>",
"msgtype": "m.notice"
}
To improve usability with different home server configurations, the bot should post a visible link which can be clicked. Ideally it could post part or all of the content from the Mastodon post as well so users would not have to click the link just to see what it's about.