There is no built-in node in Blender to visualize numeric attributes in 3D view, but Ilir Beqiri shows how you can make an attribute visualizer with Geometry Nodes.
Ilir Beqiri recently published a for Blender that shows how to build an actual attribute visualizer using purely Geometry Nodes. The visualizer is not just an index viewer but an exact float number with positive and negative ranges.
“…It is super accurate and calculates extremely fast because it generates instances only.”
Not only can you view the numbers on the 3D view, but you can also render them. Choose to follow the tutorial to build it yourself, or if you want the Node Group to use it in your project, buy it for a modest sum from here.