Titles / Headings play much more than a cosmetic role. Headings not only tidy up your page content, breaking text into manageable chunks, they also allow for far easier navigation for people accessing your site using a screen-reader (not to mention their SEO potential, covered in the SEO detail section of this manual).
The Titles/Headings table lists all those headings featured within the currently-selected Web page, along with the associated heading text. In the left column you will see the type of heading used (H1 - H6) and in the right column you will see the text that is currently used as the heading in question.
Take a moment to scroll down the list and check that the text used is appropriate for the different sections, and that an appropriate 'structure' has been used (i.e. that subheadings are indeed a level below their parent section's heading).