You can retrieve vertex attribute properties using GraphicsPipelineInfo::get_vertex_attribute_properties, but you need to provide an index, and there's no way to retrieve the number of available vertex attributes right now.
Nevermind, I just realized you can use _Anvil::GraphicsPipelineInfo::get_graphics_pipelineproperties to retrieve the number of vertex attribute properties.
You can retrieve vertex attribute properties using GraphicsPipelineInfo::get_vertex_attribute_properties, but you need to provide an index, and there's no way to retrieve the number of available vertex attributes right now.