I would expect that there are questions on sightly since it is important in AEM 6 and since it takes the place of JSP. I would review the documentation on sightly if you are not familiar with it, and go through articles links that are located on the experience delivers page.
Here are some links:
http://blogs.adobe.com/experiencedelivers/
https://docs.adobe.com/docs/en/aem/6-0/develop/sightly.html
Also, on the Adobe Experience Manager Help site, there is a tutorial on creating a sighlty component. Here is a link: https://helpx.adobe.com/experience-manager/using/creating-sightly-component.html
These are the sites that I used when I was preparing to take the exam.