If you're looking over your files to find, missing metadata might be that you discover some value for something that is called Y Resolution. The metadata can be found in images and videos specifically. But, there are other files that include some form of visualization, like documents that could contain information regarding what is known as the Y Resolution as well. As the name implies, it is the Y Resolution that hints at the resolution of the file but only to the specific axis in the direction of the y-axis.
In a coordinate system, the y-axis can also be called the secondary or vertical axis. If a file contains an amount for Y Resolution, this value is what the resolution vertical is. The value is usually, in all cases, presented in pixels. However, it could be expressed as millimeters (centimeters) or millimeters (millimeters).