That's not quite correct. It is no longer visible on the website itself, or within the mobile clients. But if you inspect the requests, you can still see things like

    source: <a href="http://twitter.com/download/iphone" rel="nofollow">Twitter for iPhone</a>

which shows the tweet was posted from iOS.

torrent metadata says it's from 2022, before it was "removed"

magnet:?xt=urn:btih:c963982c4ffa264fe76ec5918f83dd775521201b&dn=twitter_users_csv&tr=udp://tracker.openbittorrent.com:80&tr=udp://tracker.opentrackr.org:1337/announce

Yes it was removed the UI, but if you browse Twitter with developer tools open to the Network tab you can still find the posting client in the API response JSON when viewing a Tweet.