diff --git a/core/Makefile b/core/Makefile
index 2826fdc7c7..08c194b141 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -16,6 +16,52 @@ VENDOR_DLKM_NOTICE_DEPS :=
 ODM_DLKM_NOTICE_DEPS :=
 SYSTEM_DLKM_NOTICE_DEPS :=
 
+# -----------------------------------------------------------------
+# Release Config Flags
+
+# Create a summary file of build flags for each partition
+# $(1): build flags json file
+# $(2): flag names
+define generate-partition-build-flag-file
+$(eval $(strip $(1)): PRIVATE_OUT := $(strip $(1)))
+$(eval $(strip $(1)): PRIVATE_FLAG_NAMES := $(strip $(2)))
+$(strip $(1)):
+	mkdir -p $$(dir $$(PRIVATE_OUT))
+	( \
+		echo '{' ; \
+		echo 'flags: [' ; \
+		$$(foreach flag, $$(PRIVATE_FLAG_NAMES), \
+			printf '  { "name": "%s", "value": "%s", ' \
+					'$$(flag)' \
+					'$$(_ALL_RELEASE_FLAGS.$$(flag).VALUE)' \
+					; \
+			printf '"set": "%s", "default": "%s", "declared": "%s", }' \
+					'$$(_ALL_RELEASE_FLAGS.$$(flag).SET_IN)' \
+					'$$(_ALL_RELEASE_FLAGS.$$(flag).DEFAULT)' \
+					'$$(_ALL_RELEASE_FLAGS.$$(flag).DECLARED_IN)' \
+					; \
+			printf '$$(if $$(filter $$(lastword $$(PRIVATE_FLAG_NAMES)),$$(flag)),,$$(comma))\n' ; \
+		) \
+		echo "]" ; \
+		echo "}" \
+	) >> $$(PRIVATE_OUT)
+endef
+
+$(foreach partition, $(_FLAG_PARTITIONS), \
+	$(eval BUILD_FLAG_SUMMARIES.$(partition) \
+			:= $(TARGET_OUT_FLAGS)/$(partition)/etc/build_flags.json) \
+	$(eval $(call generate-partition-build-flag-file, \
+				$(BUILD_FLAG_SUMMARIES.$(partition)), \
+				$(_ALL_RELEASE_FLAGS.PARTITIONS.$(partition)) \
+            ) \
+    ) \
+)
+
+# TODO: Remove
+.PHONY: flag-files
+flag-files: $(foreach partition, $(_FLAG_PARTITIONS), \
+		$(TARGET_OUT_FLAGS)/$(partition)/etc/build_flags.json)
+
 # -----------------------------------------------------------------
 # Define rules to copy PRODUCT_COPY_FILES defined by the product.
 # PRODUCT_COPY_FILES contains words like <source file>:<dest file>[:<owner>].
diff --git a/core/envsetup.mk b/core/envsetup.mk
index e3300fcf13..8887ddcdf8 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -41,6 +41,11 @@ $(eval LOADED_STARLARK_FILES :=)
 $(eval _starlark_results :=)
 endef
 
+# ---------------------------------------------------------------
+# Release config
+include $(BUILD_SYSTEM)/release_config.mk
+
+# ---------------------------------------------------------------
 # defines ALL_VERSIONS
 $(call run-starlark,build/make/core/all_versions.bzl)
 
@@ -350,6 +355,7 @@ $(eval _dump_variables_rbc_excluded := \
   RBC_PRODUCT_CONFIG \
   RBC_BOARD_CONFIG \
   SOONG_% \
+  TARGET_RELEASE \
   TOPDIR \
   TRACE_BEGIN_SOONG \
   USER)
@@ -564,6 +570,8 @@ TARGET_OUT_ETC := $(TARGET_OUT)/etc
 TARGET_OUT_NOTICE_FILES := $(TARGET_OUT_INTERMEDIATES)/NOTICE_FILES
 TARGET_OUT_FAKE := $(PRODUCT_OUT)/fake_packages
 TARGET_OUT_TESTCASES := $(PRODUCT_OUT)/testcases
+TARGET_OUT_FLAGS := $(TARGET_OUT_INTERMEDIATES)/FLAGS
+
 .KATI_READONLY := \
   TARGET_OUT_EXECUTABLES \
   TARGET_OUT_OPTIONAL_EXECUTABLES \
@@ -577,7 +585,8 @@ TARGET_OUT_TESTCASES := $(PRODUCT_OUT)/testcases
   TARGET_OUT_ETC \
   TARGET_OUT_NOTICE_FILES \
   TARGET_OUT_FAKE \
-  TARGET_OUT_TESTCASES
+  TARGET_OUT_TESTCASES \
+  TARGET_OUT_FLAGS
 
 ifeq ($(SANITIZE_LITE),true)
 # When using SANITIZE_LITE, APKs must not be packaged with sanitized libraries, as they will not
diff --git a/core/release_config.mk b/core/release_config.mk
new file mode 100644
index 0000000000..0ad87fce25
--- /dev/null
+++ b/core/release_config.mk
@@ -0,0 +1,198 @@
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Partitions that get build system flag summaries
+_FLAG_PARTITIONS := system vendor system_ext product
+
+# All possible release flags. Defined in the flags.mk files
+# throughout the tree
+_ALL_RELEASE_FLAGS :=
+
+# -----------------------------------------------------------------
+# Choose the flag files
+# Do this first, because we're going to unset TARGET_RELEASE before
+# including anyone, so they don't start making conditionals based on it.
+
+# If this is a google source tree, restrict it to only the one file
+# which has OWNERS control.  If it isn't let others define their own.
+config_map_files := build/make/release/release_config_map.mk \
+    $(if $(wildcard vendor/google/release/release_config_map.mk), \
+        vendor/google/release/release_config_map.mk, \
+        $(sort \
+            $(wildcard device/*/release/release_config_map.mk) \
+            $(wildcard device/*/*/release/release_config_map.mk) \
+            $(wildcard vendor/*/release/release_config_map.mk) \
+            $(wildcard vendor/*/*/release/release_config_map.mk) \
+        ) \
+    )
+
+# $1 config name
+# $2 release config files
+define declare-release-config
+    $(eval # No duplicates)
+    $(if $(filter $(_all_release_configs), $(strip $(1))), \
+        $(error declare-release-config: config $(strip $(1)) declared in: $(_included) Previously declared here: $(_all_release_configs.$(strip $(1)).DECLARED_IN)) \
+    )
+    $(eval # Must have release config files)
+    $(if $(strip $(2)),,  \
+        $(error declare-release-config: config $(strip $(1)) must have release config files) \
+    )
+    $(eval _all_release_configs := $(sort $(_all_release_configs) $(strip $(1))))
+    $(eval _all_release_configs.$(strip $(1)).DECLARED_IN := $(_included))
+    $(eval _all_release_configs.$(strip $(1)).FILES := $(strip $(2)))
+endef
+
+# Include the config map files
+$(foreach f, $(config_map_files), \
+    $(eval _included := $(f)) \
+    $(eval include $(f)) \
+)
+
+# If TARGET_RELEASE is set, fail if there is no matching release config
+# If it isn't set, no release config files will be included and all flags
+# will get their default values.
+ifneq ($(TARGET_RELEASE),)
+ifeq ($(filter $(_all_release_configs), $(TARGET_RELEASE)),)
+    $(error No release config found for TARGET_RELEASE: $(TARGET_RELEASE))
+else
+    # Choose flag files
+    # Don't sort this, use it in the order they gave us.
+    _release_config_files := $(_all_release_configs.$(TARGET_RELEASE).FILES)
+endif
+else
+# Useful for finding scripts etc that aren't passing or setting TARGET_RELEASE
+ifneq ($(FAIL_IF_NO_RELEASE_CONFIG),)
+    $(error FAIL_IF_NO_RELEASE_CONFIG was set and TARGET_RELEASE was not)
+endif
+_release_config_files :=
+endif
+
+# Unset variables so they can't use it
+define declare-release-config
+$(error declare-release-config can only be called from inside release_config_map.mk files)
+endef
+
+# TODO: Remove this check after enough people have sourced lunch that we don't
+# need to worry about it trying to do get_build_vars TARGET_RELEASE. Maybe after ~9/2023
+ifneq ($(CALLED_FROM_SETUP),true)
+define TARGET_RELEASE
+$(error TARGET_RELEASE may not be accessed directly. Use individual flags.)
+endef
+else
+TARGET_RELEASE:=
+endif
+.KATI_READONLY := TARGET_RELEASE
+
+$(foreach config, $(_all_release_configs), \
+    $(eval _all_release_configs.$(config).DECLARED_IN:= ) \
+    $(eval _all_release_configs.$(config).FILES:= ) \
+)
+_all_release_configs:=
+config_map_files:=
+
+# -----------------------------------------------------------------
+# Declare the flags
+
+# $1 partition(s)
+# $2 flag name. Must start with RELEASE_
+# $3 default. True or false
+define declare-build-flag
+    $(if $(filter-out all $(_FLAG_PARTITIONS), $(strip $(1))), \
+        $(error declare-build-flag: invalid partitions: $(strip $(1))) \
+    )
+    $(if $(and $(filter all,$(strip $(1))),$(filter-out all, $(strip $(1)))), \
+        $(error declare-build-flag: "all" can't be combined with other partitions: $(strip $(1))), \
+        $(eval declare-build-flag.partition := $(_FLAG_PARTITIONS)) \
+    )
+    $(if $(filter-out RELEASE_%, $(strip $(2))), \
+        $(error declare-build-flag: Release flag names must start with RELEASE_: $(strip $(2))) \
+    )
+    $(eval _ALL_RELEASE_FLAGS += $(strip $(2)))
+    $(foreach partition, $(declare-build-flag.partition), \
+        $(eval _ALL_RELEASE_FLAGS.PARTITIONS.$(partition) := $(sort \
+            $(_ALL_RELEASE_FLAGS.PARTITIONS.$(partition)) $(strip $(2)))) \
+    )
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).PARTITIONS := $(declare-build-flag.partition))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).DEFAULT := $(strip $(3)))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).DECLARED_IN := $(_included))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).VALUE := $(strip $(3)))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(2)).SET_IN := $(_included))
+    $(eval declare-build-flag.partition:=)
+endef
+
+
+# Choose the files
+# If this is a google source tree, restrict it to only the one file
+# which has OWNERS control.  If it isn't let others define their own.
+flag_declaration_files := build/make/release/flags.mk \
+    $(if $(wildcard vendor/google/release/flags.mk), \
+        vendor/google/release/flags.mk, \
+        $(sort \
+            $(wildcard device/*/release/flags.mk) \
+            $(wildcard device/*/*/release/flags.mk) \
+            $(wildcard vendor/*/release/flags.mk) \
+            $(wildcard vendor/*/*/release/flags.mk) \
+        ) \
+    )
+
+# Include the files
+$(foreach f, $(flag_declaration_files), \
+    $(eval _included := $(f)) \
+    $(eval include $(f)) \
+)
+
+# Don't let anyone declare build flags after here
+define declare-build-flag
+$(error declare-build-flag can only be called from inside flag definition files.)
+endef
+
+# No more flags from here on
+.KATI_READONLY := _ALL_RELEASE_FLAGS
+
+# -----------------------------------------------------------------
+# Set the flags
+
+# $(1): Flag name. Must start with RELEASE_ and have been defined by declare-build-flag
+# $(2): Value. True or false
+define set-build-flag
+    $(if $(filter-out $(_ALL_RELEASE_FLAGS), $(strip $(1))), \
+        $(error set-build-flag: Undeclared build flag: $(strip $(1))) \
+    )
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(1)).VALUE := $(strip $(2)))
+    $(eval _ALL_RELEASE_FLAGS.$(strip $(1)).SET_IN := $(_included))
+endef
+
+# Include the files (if there are any)
+$(foreach f, $(_release_config_files), \
+    $(eval _included := $(f)) \
+    $(eval include $(f)) \
+)
+
+# Don't let anyone declare build flags after here
+define set-build-flag
+$(error set-build-flag can only be called from inside release config files.)
+endef
+
+# Set the flag values, and don't allow any one to modify them.
+$(foreach flag, $(_ALL_RELEASE_FLAGS), \
+    $(eval $(flag) := $(_ALL_RELEASE_FLAGS.$(flag).VALUE)) \
+    $(eval .KATI_READONLY := $(flag)) \
+)
+
+# -----------------------------------------------------------------
+# Clear out vars
+flag_declaration_files:=
+flag_files:=
+_included:=
+_release_config_files:=
diff --git a/envsetup.sh b/envsetup.sh
index 916344cd31..ef4824938c 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -842,7 +842,7 @@ function lunch()
     export TARGET_PRODUCT=$(get_build_var TARGET_PRODUCT)
     export TARGET_BUILD_VARIANT=$(get_build_var TARGET_BUILD_VARIANT)
     if [ -n "$release" ]; then
-      export TARGET_RELEASE=$(get_build_var TARGET_RELEASE)
+      export TARGET_RELEASE=$release
     else
       unset TARGET_RELEASE
     fi
diff --git a/release/flags.mk b/release/flags.mk
new file mode 100644
index 0000000000..eb97dc1fba
--- /dev/null
+++ b/release/flags.mk
@@ -0,0 +1,23 @@
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This file defines the build system flags that can be set based on the
+# release configuration.  If at all possible, use aconfig flags instead.
+# This is for things that must be decided at compile time.
+
+# Flag names should be alphabetical by flag name.
+
+$(call declare-build-flag, system, RELEASE_THE_FIRST_FLAG, true)
+$(call declare-build-flag, system, RELEASE_THE_SECOND_FLAG, true)
+
diff --git a/release/release_config_map.mk b/release/release_config_map.mk
new file mode 100644
index 0000000000..190cb8930b
--- /dev/null
+++ b/release/release_config_map.mk
@@ -0,0 +1,16 @@
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# AOSP doesn't define any release configs yet.
+