How do I view the properties of an abstract class?

Call the properties function with the name of the Abstract class as input.

>> properties AbstractClassDemo
Properties for class AbstractClassDemo:

    one
    two

Alternately if you want additional information you could use either the ? operator or the meta.class.fromName function to create the meta.class object for the class. That object has an array of meta.property objects in its PropertyList property.

>> q = meta.class.fromName('AbstractClassDemo');
>> q = ?AbstractClassDemo;
>> propOne = q.PropertyList(1)

propOne = 

  property with properties:

                    Name: 'one'
             Description: ''
     DetailedDescription: ''
*snip the rest of the properties to keep this post short*