I have since installed Iron, and done some checking with the source. It appears SRWare has made the following changes (this is based on the Babel translation of the page in German, so is fuzzy):
- They are using 525.19 of Webkit rather than Chrome's current 525.13.
- The unique clientID has been removed.
- The TimeStamp for Chrome's install date has been removed.
- Each keypress from the Suggest feature is no longer sent to Google.
- Google-hosted alternative error messages have been disabled.
- RLZ encoding of information to Google, such as where Chrome was downloaded and other configuration options has been removed.
- The persistent GoogleUpdater services has been disabled (this isn't removed when you uninstall Chrome).
- Something about the homepage and URL tracking has been removed.
Hat tip to cocooncrash for the link.