curiouser and curiouser regarding Průhonice Park and Prague's boundaries!
The Reactive Monitoring Review report indicates that a request was received in June 1992 to include this park as an addition to the Nomination file of Sep 1991. No specific mention of this was made in the record of the inscription at the Dec 92 WHC in Santa Fe and, as David has pointed out, the UNESCO Web site makes no mention of it being either an integral or separate part of the park.
A Google search on "Průhonice Park" retrieves loads of sites stating "Průhonice Castle and the adjacent beautiful park that is protected by UNESCO. ..." -obviously all sourcing their comments from the same place!
A couple state "under application to be a UNESCO protected area" and that it "is ranking high on the list of future UNESCO World Heritage Sites" - obviously "incorrectly" but perhaps indicating that, at some time it was going to be handled separately!!
But, perhaps most interesting, are those which indicate the "reason" for its inclusion - rather than the aforementioned "Castle" which might have seemed the most likely??
"Thanks to its many varieties of woody plants, this park is protected by Unesco. ..."!!!
Several mention that there is a botanical park and an English Garden but without giving them as the reason for inscription. But what has any of this got to do with the criteria under which Prague was inscribed??
It does appear that it is as a Botanical Garden that the park is particularly noted - Further searches identify that the "The Silva Tarouca Research Institute for Landscape and Ornamental Gardening" is situated there - but its Website makes no mention of its grounds being UNESCO inscribed.
So it looks like 2 more "Connections" for Prague, Els - Botanical and English Gardens? But no great clarity as to how/why the park got added late on to the Prague nomination
But further to this - if it seems strange that this site which seems to bear no relationship to the Old City of Prague should be have been added, have a look at the Czech Republic's T List for yet more possible "additions" to the Prague site - http://www.worldheritagesite.org/sites/t1565.html
. A 1920's villa, an abbey and a hunting lodge are all under consideration!