Besides the usual internal and public bug fixes, the main addition to Vulkan 1.2.177 is the VK_EXT_provoking_vertex extension. VK_EXT_provoking_vertex is for changing the provoking vertex convention from the default of the first vertex to instead the last vertex. This change is to match the OpenGL convention of using the last vertex.
With the provoking vertex extension being to match the OpenGL behavior, the extension is intended to help with API translation layer projects working to run OpenGL over Vulkan. The provoking vertex extension was worked on by engineers from Google, NVIDIA, Intel, AMD, and other organizations – including Mike Blumenkrantz of Valve who is known for his work on the Zink OpenGL-over-Vulkan Mesa code. Thus we’ll probably see Zink beginning to make use of VK_EXT_provoking_vertex in short order.