There is no cross-vendor mesh shader support in Vulkan yet.
I've said this before, but there really is no need to request core API features to be implemented (especially when nothing relevant uses them yet). We'll get to them eventually.
This is implemented now.
Nothing extracted yet.
https://store.steampowered.com/app/1498800/3DMark_Mesh_Shader_feature_test/?l=english
Requires 3dmark.
https://www.youtube.com/watch?v=qlwR_9AAAVc 3DMark Mesh Shader Feature Test