The way mute lists work now is that mutes are either public or private (encrypted). Amethyst for example uses private mutes only, which is better for privacy, but also means other people, as well as external tools can't see who muted who anymore.  

 See NIP-51 https://github.com/nostr-protocol/nips/blob/master/51.md 

 Thanks for the info! 

 Damus uses afaik still the old kind 30000 which complicates things even further 🥲