Looking at the current git checkout of release-notes, I can't find any mention of Features/1000SystemAccounts.
A proposed text is at https://fedoraproject.org/wiki/Features/1000SystemAccounts#Release_Notes ; I'm not where it would fit best - somewhere in the "Changes in Fedora for System Administrators" section, perhaps under "security".
Version-Release number of selected component (if applicable):
release-notes commit 28cf76e4f29e6d2a6edb1d748493718b44d7ffe4
Done, with some minor rewording. (We don't like to say "see" in documents, preferring phrases like "refer to" or "reference".)
commit - a747533f580d1fc5a2d444917834671e16075589
Should have been autoclosed by Bodhi,