P5 -> portal_properties/site_properties?

In Plone 5, where are the "portal_properties/site_properties" properties??

In Plone 4.xx there are some very useful properties there to change!

Upgrading Plone 4.x to 5.0

Sorry, did not understood your answer, maybe I've expressed myself wrong.

What I mean is how in Plone 5 can I change some properties, like

oh, I thought my PR got merged already...
Here you should find more information:

Ok, thank you.
Unfortunatly it seems that some of the properties are not present (or at least available to change TTW) in P5.

Maybe not in a dedicated Control Panel.
I could not finish the upgrade documentation, some items have a TBD, in that case I did not check yet. They could have gotten a different name, but this rarely happened.
Have you tried the search in the configuration registry?
Everything that did not get removed became a registry entry. Every registry entry gets TTW functionality in the configuration registry for free.

The portal_properties tool was removed in Plone 5; site properties are available via the Plone registry.

I think in Plone 5 there is still a "portal_properties (General settings registry)" tool, but it is empty it seems....???

I can see it too, maybe it is there for backward compatibility with addons who stored their own properties there.
If you readd customizations there, they will be ignored by plone core. Plone core has the portal_properties in the Plone registry too.
My PR from yesterday was merged, the link in my first reply now shows a few portal_properties and how to access them now.