diff --git a/target/product/sdk_phone_arm64.mk b/target/product/sdk_phone_arm64.mk
index c770663..a689475 100644
--- a/target/product/sdk_phone_arm64.mk
+++ b/target/product/sdk_phone_arm64.mk
@@ -23,6 +23,9 @@
 $(call inherit-product, $(SRC_TARGET_DIR)/product/sdk_base.mk)
 $(call inherit-product, $(SRC_TARGET_DIR)/board/generic_arm64/device.mk)
 
+# AOSP emulator images build the AOSP messaging app.
+# Google API images override with the Google API app.
+# See vendor/google/products/sdk_google_phone_*.mk
 PRODUCT_PACKAGES += \
     messaging
 
diff --git a/target/product/sdk_phone_armv7.mk b/target/product/sdk_phone_armv7.mk
index 0851318..ebdd0e7 100644
--- a/target/product/sdk_phone_armv7.mk
+++ b/target/product/sdk_phone_armv7.mk
@@ -16,6 +16,9 @@
 
 $(call inherit-product, $(SRC_TARGET_DIR)/product/sdk_base.mk)
 
+# AOSP emulator images build the AOSP messaging app.
+# Google API images override with the Google API app.
+# See vendor/google/products/sdk_google_phone_*.mk
 PRODUCT_PACKAGES += \
     messaging
 
diff --git a/target/product/sdk_phone_mips.mk b/target/product/sdk_phone_mips.mk
index 2f577d3..1cc2fe4 100644
--- a/target/product/sdk_phone_mips.mk
+++ b/target/product/sdk_phone_mips.mk
@@ -21,6 +21,9 @@
 
 $(call inherit-product, $(SRC_TARGET_DIR)/product/sdk_base.mk)
 
+# AOSP emulator images build the AOSP messaging app.
+# Google API images override with the Google API app.
+# See vendor/google/products/sdk_google_phone_*.mk
 PRODUCT_PACKAGES += \
     messaging
 
diff --git a/target/product/sdk_phone_mips64.mk b/target/product/sdk_phone_mips64.mk
index 2c05f31..e45d71b 100644
--- a/target/product/sdk_phone_mips64.mk
+++ b/target/product/sdk_phone_mips64.mk
@@ -22,6 +22,9 @@
 $(call inherit-product, $(SRC_TARGET_DIR)/product/core_64_bit.mk)
 $(call inherit-product, $(SRC_TARGET_DIR)/product/sdk_base.mk)
 
+# AOSP emulator images build the AOSP messaging app.
+# Google API images override with the Google API app.
+# See vendor/google/products/sdk_google_phone_*.mk
 PRODUCT_PACKAGES += \
     messaging
 
diff --git a/target/product/sdk_phone_x86.mk b/target/product/sdk_phone_x86.mk
index 2feb6cc..01c2e83 100644
--- a/target/product/sdk_phone_x86.mk
+++ b/target/product/sdk_phone_x86.mk
@@ -21,6 +21,9 @@
 
 $(call inherit-product, $(SRC_TARGET_DIR)/product/sdk_base.mk)
 
+# AOSP emulator images build the AOSP messaging app.
+# Google API images override with the Google API app.
+# See vendor/google/products/sdk_google_phone_*.mk
 PRODUCT_PACKAGES += \
     messaging
 
diff --git a/target/product/sdk_phone_x86_64.mk b/target/product/sdk_phone_x86_64.mk
index f3573a2..c3bc5e9 100644
--- a/target/product/sdk_phone_x86_64.mk
+++ b/target/product/sdk_phone_x86_64.mk
@@ -22,6 +22,9 @@
 $(call inherit-product, $(SRC_TARGET_DIR)/product/core_64_bit.mk)
 $(call inherit-product, $(SRC_TARGET_DIR)/product/sdk_base.mk)
 
+# AOSP emulator images build the AOSP messaging app.
+# Google API images override with the Google API app.
+# See vendor/google/products/sdk_google_phone_*.mk
 PRODUCT_PACKAGES += \
     messaging