What is the technology here(IEnumerable)?

I know the linq codeis for loop over a query.

IEnumerable<int> result = from value in Enumerable.Range(0, 2)
                                  select value;

Also I know how to implement the IEnumerable<T> interface below.

// A custom class that implements IEnumerable(T). When you implement IEnumerable(T),  
// you must also implement IEnumerable and IEnumerator(T). 
public class StreamReaderEnumerable : IEnumerable<string>
{

    private string _filePath;
    public StreamReaderEnumerable(string filePath)
    {
        _filePath = filePath;
    }


    // Must implement GetEnumerator, which returns a new StreamReaderEnumerator. 
    public IEnumerator<string> GetEnumerator()
    {
        return new StreamReaderEnumerator(_filePath);
    }

    // Must also implement IEnumerable.GetEnumerator, but implement as a private method. 
    private IEnumerator GetEnumerator1()
    {
        return this.GetEnumerator();
    }
    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator1();
    }

}

Now I have the code below.

static class Program
    {
        static void Main()
        {
            var obj = new object();
            int count = AllParents(obj).Count(); // Using Linq only here.
            Console.WriteLine(count);
        }

        public static IEnumerable<object> AllParents(object obj)
        {
            while (true)
            {
                obj = GetParentObject(obj);

                if (obj == null)
                    yield break;

                yield return obj;
            }
        }

        // This is merely a hacky test implementation.
        public static object GetParentObject(object obj)
        {
            if (--count == 0)
                return null;

            return obj;
        }

        private static int count = 10;
    }

I don't know what is the best term to describe the method.

public static IEnumerable<object> AllParents(object obj){ blah blah}