Never mind I think I found it. I will use this as a test post!
Yep, looks like you found it!
Pro tip: When you make updates, a test post isn't necessary... all of your past posts will have your new signature. I like to open a separate tab with an old post pulled up, and I just 'refresh' the tab with the old post as I make changes; that way I can see how it looks as I go.