Whenever you or an other player in the world uses a spyglass, an error message will appear.

When i used the spyglass on my friend (who has the ''Nether Tamer'' skin equipped) there is this message:

''[Molang][error]-minecraft:player.0.5a5dcffc-f194-4a8b-a7b7-94fa7997a434.NetherTamer1b99b77c-3caa-4aaa-8f79-f79f053e586f | binding expression q.item_slot_to_bone_name(q.main_hand_item_use_duration > 0.0f? 'head' : 'main_hand') returned a bone name that doesn't exist.

It isn't a chat message, it just sits on top of your screen.

Another message that came after that was:

''[Molang][error]-minecraft:player.0.5a5dcffc-f194-4a8b-a7b7-94fa7997a434.NetherTamer1b99b77c-3caa-4aaa-8f79-f79f053e586f | binding expression q.item_slot_to_bone_name(q.main_hand_item_use_duration > 0.0f? 'head' : 'main_hand') did not return a name?

Since the name of my friend's skin is there, i think it depends on what you are looking at.

The name of the .png file also has the same characters as the message.