By default, the column headers in exported spreadsheets are prefixed by a tag, like this: >>L<<. These Annotated Field Headers allow to preserve more complex termbase setups with fields on multiple levels. It's recommended to use tags, especially if you ever want to convert the spreadsheet back. But if you don't want to go back, you can switch them off, so the spreadsheet looks nicer.
Equivalent settings xml
Created with the Personal Edition of HelpNDoc: Easily create PDF Help documents