Hit collapse parentheses (under the preferences panel) to see the difference.
On top of that, you can fine-tune your reading experiencing by tweaking around the options (to come up with your optimal preferences).
Enable the show word count option to see how many words are collapsed inside each parenthesis pair (the word count will not be displayed on a count lower or equal to your short word count definition).
Enable expand short on hover (quick view/reveal) to auto expand short parentheses on hover (to allow you to do text operations, like selection and copying of text inside the parentheses, you have to collapse by click again).
What short (actually) means is a matter of words defined by the short word count option.
Source code and other unwanted content is not affected by default (you can change this behavior by don't ignoring the corresponding HTML element tags like: `code`).