I was wondering where you can find more information about TWHS since - unless I missed something - the info on the official Unesco website is very limited. I've noticed there are some specific websites (e.g. Naumburg), but it seems that these are the exception.

It would be interesting to see what exactly is included (e.g. maps), but maybe more details are only available later in the recognition procedure?

Yes, only when the sites are officially nominated they create a nomination dossier with all the full data (including maps). To submit a Tentative List. only a short form has to be filled in, and it doesn't seem to be checked for completeness or whether it makes sense. Sometimes the TWHS are mere 'ideas'