This is the "Index" tab from "Project | Documentation Options".
Here you specify the text that will appear on the top of your Index page. You can also format it and set the font settings and alignment.
Use Alphabetical Headings
If this option is checked the leading letter, i.e. "-A-" will appear before each block of common letters. You can control the font settings here.
This is where you set the font settings for the look of the keywords.