All non-CMS Luminate Online pages are generated via templates. For those templates to work, they need to have variables that are local to that specific template. A-tags are how templates handle variables local to that template. The way that you affect those is by using the product. For example, in the case of the [[A13=addtional meta tags]], if you edit a PageWrapper and go to step 2 Meta Tags and put content in the Additional HTML Tags for HEAD Element field, the A13 tag will pull in what you put in that field.