Unsure if there's a better way than simply just sending an empty signature over.

This should solve this bungee & spigot-side as well (bungee doesn't need modifying as it doesn't have modern forwarding like velocity, fixing spigot also fixes bungee)

https://github.com/GeyserMC/Floodgate/blob/master/bungee%2Fsrc%2Fmain%2Fjava%2Forg%2Fgeysermc%2Ffloodgate%2Flistener%2FBungeeListener.java#L134

https://github.com/GeyserMC/Floodgate/blob/master/spigot%2Fsrc%2Fmain%2Fjava%2Forg%2Fgeysermc%2Ffloodgate%2Flistener%2FPaperProfileListener.java
There are also these two occurrences where we're currently setting an empty skin - maybe it is worth it to change these too? Just for consistency

https://github.com/GeyserMC/Floodgate/blob/master/bungee%2Fsrc%2Fmain%2Fjava%2Forg%2Fgeysermc%2Ffloodgate%2Flistener%2FBungeeListener.java#L134

https://github.com/GeyserMC/Floodgate/blob/master/spigot%2Fsrc%2Fmain%2Fjava%2Forg%2Fgeysermc%2Ffloodgate%2Flistener%2FPaperProfileListener.java There are also these two occurrences where we're currently setting an empty skin - maybe it is worth it to change these too? Just for consistency

Yep, believe this would be ideal. 33fd6ac

One functional thing to keep in mind is that with this PR you always prevent the skin lookup, while you still want to do a skin lookup when the player is linked. When a player is linked it acts like it's the linked Java player (including the same UUID etc.), meaning that it should also have the skin of the Java player. Which is something we don't store, and has to be looked up like normal.

Would you recommend not adding the properties if the player is linked?

One functional thing to keep in mind is that with this PR you always prevent the skin lookup, while you still want to do a skin lookup when the player is linked. When a player is linked it acts like it's the linked Java player (including the same UUID etc.), meaning that it should also have the skin of the Java player. Which is something we don't store, and has to be looked up like normal.

Would you recommend not adding the properties if the player is linked?

Or, alternatively, look them up ourselves?

If the player is linked, the Java server will see a valid Java username/uuid, and should look up textures for that player

If the player is linked, the Java server will see a valid Java username/uuid, and should look up textures for that player

I believe we should be doing skin lookups on velocity ourselves then, having spigot handle it if floodgate's ran purely on spigot is fine, however you don't want spigot instances doing a new lookup every time a player switches server on velocity (modern forwarding).

If the player is linked, the Java server will see a valid Java username/uuid, and should look up textures for that player

Should be good to merge now