ahhh now I see. I didn't scroll far enough in your original to see the 1, 2 values
Contour function—ArcGIS Pro | Documentation
The contours generated from the elevation dataset are rasters with a value of one (1). The bold index contour has a value of two (2). Use Identify to display the elevation value of the contour based on the source elevation layer, which will return the elevation of the contour, point, key features, and spot heights on the maps and images.
... sort of retired...