3.0.0: Expand release highlights section

Expand the section describing removal of GWT and ReviewDb.

Change-Id: I9acb9676ff33265f0c7a44c50018ae4d93b5d636
diff --git a/pages/site/releases/3.0.md b/pages/site/releases/3.0.md
index 557aa91..cc08204 100644
--- a/pages/site/releases/3.0.md
+++ b/pages/site/releases/3.0.md
@@ -8,9 +8,14 @@
 
 ## Release Highlights
 
-* Removal of GWTUI
+* Removal of GWT UI
 
-* Removal of ReviewDB
+  The GWT UI is removed and PolyGerrit is now the only UI.
+
+* Removal of ReviewDb
+
+  The database backend for changes, accounts, groups and projects ("ReviewDb") is
+  removed and all metadata is now stored in git ("NoteDb").
 
 ## Important Notes
 
diff --git a/pages/site/releases/README.md b/pages/site/releases/README.md
index 7e9f447..ac25f4e 100644
--- a/pages/site/releases/README.md
+++ b/pages/site/releases/README.md
@@ -20,9 +20,10 @@
 
 ## 3.0.0 *(release candidate)*
 
-* Removal of GWTUI.
+* The GWT UI is removed and PolyGerrit is now the only UI.
 
-* Removal of ReviewDB.
+* The database backend for changes, accounts, groups and projects ("ReviewDb") is
+removed and all metadata is now stored in git ("NoteDb").
 
 [Release notes for Gerrit 3.0](/3.0.md)