How to install additional system components in Xcode 8

Question

I installed Xcode 8.0 and the comment selector + / command key stopped working.

In the Xcode 8 release notes, he mentions extensions to the source code editor and says the following:

To use the Comment / Uncomment Selection and Add Documentation editor comments, as well as other installed Xcode Extensions on OS X version 10.11, start Xcode and install additional system components, and then restart your Mac. (26106213)

How to do it?

Please note that this is not like "Additional_Tools_for_Xcode_8"

Also because the + / command is serformed in the Xcode-> Structure menue editor for some of them: sudo / usr / libexec / xpccachectl I did this and now the + / command is not gray, but still does not work.
Can someone also figure out what the xpccachectl executable does?

Thanks.