Time to summarise this topic:
In SFOS until 4.6 there is a /usr/bin/unzip. Some apps (also in store) use this command.
In SFOS 5.0 there is no /usr/bin/unzip installed but this is can installed with Requires: unzip. But this is not allowed for harbour apps (-> store). There is no reasons named for this in this thread.
Thanks for discussing my point here in this thread.