New MacBook Pro's with Touch Bar, in macOS Sierra, icons for the system control strip, where would they be located?
I looked under HD/System/Library/CoreServices, not there.....
The Touch Bar system icons are all located in /System/Library/CoreServices/SystemAppearance.bundle/Contents/Resources/Assets.car
.
To name a few examples, they are named like TouchBarControlStripSpotlight
or TouchBarControlStripSiriContent
.
If you want to inspect and also change them you can use the ThemeEngine app to open the .CAR files. You can find the app/project here: https://github.com/alexzielenski/ThemeEngine
Sadly the ThemeEngine.app fails to display all icons. Some appear to be empty, but I guess thats a problem with the app. Maybe there's another, more reliable way to open .CAR files.