The description can be seen in the hint of the file or in the second line of the General tab of the file properties.
The older versions of Windows allowed editing the file description. It was useful (as a hint). Now the field "description" is readable, contains useless information by default (such as the full name of the file), and I cannot find how it can be changed.
The Details panel simply does not show the description field.
Default Programs Editor (https://superuser.com/a/483349/134259) only promises it does, but really it edits the extensions' description. It is not the description of the specific file.
