--- a/CLOBBER
+++ b/CLOBBER
@@ -17,9 +17,9 @@
 #
 # Modifying this file will now automatically clobber the buildbot machines \o/
 #
 
 # Are you updating CLOBBER because you think it's needed for your WebIDL
 # changes to stick? As of bug 928195, this shouldn't be necessary! Please
 # don't change CLOBBER for WebIDL changes any more.
 
-Bug 1714933 - Update to ICU 69 requires clobber
+Merge day clobber
\ No newline at end of file

--- a/browser/config/mozconfigs/linux32/l10n-mozconfig
+++ b/browser/config/mozconfigs/linux32/l10n-mozconfig
@@ -1,10 +1,10 @@
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
-ac_add_options --with-branding=browser/branding/nightly
+ac_add_options --enable-official-branding
 ac_add_options --disable-nodejs
 
 . "$topsrcdir/build/mozconfig.no-compile"
 
 if test `uname -m` = "x86_64"; then
   ac_add_options --target=i686-pc-linux
   ac_add_options --host=i686-pc-linux
 fi

--- a/browser/config/mozconfigs/linux64/l10n-mozconfig
+++ b/browser/config/mozconfigs/linux64/l10n-mozconfig
@@ -1,10 +1,10 @@
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
-ac_add_options --with-branding=browser/branding/nightly
+ac_add_options --enable-official-branding
 
 . "$topsrcdir/build/mozconfig.no-compile"
 ac_add_options --disable-nodejs
 
 export MOZILLA_OFFICIAL=1
 
 # Don't autoclobber l10n, as this can lead to missing binaries and broken builds
 # Bug 1283438

--- a/browser/config/mozconfigs/macosx64/l10n-mozconfig
+++ b/browser/config/mozconfigs/macosx64/l10n-mozconfig
@@ -5,17 +5,17 @@ if test `uname -s` = "Linux"; then
   # We need to indicate the target for cross builds
   ac_add_options --target=x86_64-apple-darwin
   export MKFSHFS=$MOZ_FETCHES_DIR/hfsplus-tools/newfs_hfs
   export DMG_TOOL=$MOZ_FETCHES_DIR/dmg/dmg
   export HFS_TOOL=$MOZ_FETCHES_DIR/dmg/hfsplus
 fi
 
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
-ac_add_options --with-branding=browser/branding/nightly
+ac_add_options --enable-official-branding
 
 ac_add_options --disable-nodejs
 unset NODEJS
 
 export MOZILLA_OFFICIAL=1
 
 # Don't autoclobber l10n, as this can lead to missing binaries and broken builds
 # Bug 1283438

--- a/browser/config/mozconfigs/win32/l10n-mozconfig
+++ b/browser/config/mozconfigs/win32/l10n-mozconfig
@@ -1,14 +1,14 @@
 . "$topsrcdir/browser/config/mozconfigs/common"
 . "$topsrcdir/browser/config/mozconfigs/win32/common-win32"
 . "$topsrcdir/build/mozconfig.no-compile"
 
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
-ac_add_options --with-branding=browser/branding/nightly
+ac_add_options --enable-official-branding
 
 ac_add_options --disable-nodejs
 unset NODEJS
 
 export MOZILLA_OFFICIAL=1
 
 # Don't autoclobber l10n, as this can lead to missing binaries and broken builds
 # Bug 1283438

--- a/browser/config/mozconfigs/win64-aarch64/l10n-mozconfig
+++ b/browser/config/mozconfigs/win64-aarch64/l10n-mozconfig
@@ -1,14 +1,14 @@
 . "$topsrcdir/browser/config/mozconfigs/common"
 . "$topsrcdir/browser/config/mozconfigs/win64-aarch64/common-win64"
 . "$topsrcdir/build/mozconfig.no-compile"
 
 ac_add_options --enable-update-channel="${MOZ_UPDATE_CHANNEL}"
-ac_add_options --with-branding=browser/branding/nightly
+ac_add_options --enable-official-branding
 
 ac_add_options --disable-nodejs
 unset NODEJS
 
 export MOZILLA_OFFICIAL=1
 
 # Don't autoclobber l10n, as this can lead to missing binaries and broken builds
 # Bug 1283438

--- a/browser/config/mozconfigs/win64/l10n-mozconfig
+++ b/browser/config/mozconfigs/win64/l10n-mozconfig
@@ -1,14 +1,14 @@
 . "$topsrcdir/browser/config/mozconfigs/common"
 . "$topsrcdir/browser/config/mozconfigs/win64/common-win64"
 . "$topsrcdir/build/mozconfig.no-compile"
 
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
-ac_add_options --with-branding=browser/branding/nightly
+ac_add_options --enable-official-branding
 
 ac_add_options --disable-nodejs
 unset NODEJS
 
 export MOZILLA_OFFICIAL=1
 
 # Don't autoclobber l10n, as this can lead to missing binaries and broken builds
 # Bug 1283438

--- a/browser/config/version.txt
+++ b/browser/config/version.txt
@@ -1,1 +1,1 @@
-91.0a1
+91.0

--- a/browser/config/version_display.txt
+++ b/browser/config/version_display.txt
@@ -1,1 +1,1 @@
-91.0a1
+91.0b1

--- a/config/milestone.txt
+++ b/config/milestone.txt
@@ -5,9 +5,9 @@
 #    x.x.x.x
 #    x.x.x+
 #
 # Referenced by build/moz.configure/init.configure.
 # Hopefully I'll be able to automate replacement of *all*
 # hardcoded milestones in the tree from these two files.
 #--------------------------------------------------------
 
-91.0a1
+91.0