Mantle & vulkan-grkv project

i have a problem with this project : GitHub - libcg/grvk: Vulkan-based Mantle API implementation (WIP)

i know the project is a Mantle to Vulkan translation layer

my question is : where is mantle in the source code ? , the last upadte of the project is december 2021
and mantle have disapear before to become vulkan

anyone can help me ?