Vulkano is a somewhat higher level library which aims to be safe and idiomatic. It looks like it generates its own Vulkan bindings directly from the vk.xml definitions, but it also depends on Ash, and this comment suggests that both generators need to be kept in sync so they're effectively beholden to Ash's release cadence anyway.

https://github.com/vulkano-rs/vulkano/blob/master/Cargo.toml...

Maybe that's so they can interop with other crates which use Ash's types?