Ah dot notation…
If you look closely in the Levels section of your library why Name and Elevation work will be more clear… there is a method to get the name via a Level.Name and a Level.Elevation node… you’ve got a as your input variable
x so you are able to call the methods which apply to those objects rather easily by adding the dot and typing the function name.
This section of the primer gives a solid explanation of what’s happening here and is worth review: https://www.dynamoprimer.com/07_Code-Block/7-2_Design-Script-syntax.html
Another node which you can call this way should also exist in the same section of the library: https://dictionary.dynamobim.com/#/Revit/Elements/Level/Query/ProjectElevation
Try to call that in a code block.
You can go a step further as a Level is also a type of Element so any Element method will also work (such as Element.Parameters), as long as the object has an associated result in Revit.