This is Baleen, an RSS and Podcast feed filtering application. If you're here because you've spotted the user agent in your logs, it's because someone is using this application to produce a filtered RSS feed.
Baleen will always use the user agent Baleen/1.0 (https://baleen.lewisdale.dev), and should respect robots.txt.
If you're blocking Baleen, but we're still appearing in your logs, please get in touch with the developer, as this is likely a bug in the software.