Advanced FAQ manager WordPress plugin uses two custom taxonomies – Category & Topic to categories the FAQ contents. However, there are not too many differences between these two taxonomies. You can use one of them or use both, and it depends on your requirement.
In the past, several buyers requested to add Topic taxonomy that allows them to assign the same FAQ item to different category/topic. That helps them to display FAQ posts into different areas of their website. If FAQ author changes into FAQ content, site users can get the updated information in all places. You check the following documentation link to get more idea about them.
Hope that helps.
Last Update: April 6, 2019