diff --git a/common/constants.cc b/common/constants.cc
index fa13a38..c85ba54 100644
--- a/common/constants.cc
+++ b/common/constants.cc
@@ -108,6 +108,7 @@
 const char kPrefsWallClockScatteringWaitPeriod[] = "wall-clock-wait-period";
 const char kPrefsWallClockStagingWaitPeriod[] =
     "wall-clock-staging-wait-period";
+const char kPrefsManifestBytes[] = "manifest-bytes";
 
 // These four fields are generated by scripts/brillo_update_payload.
 const char kPayloadPropertyFileSize[] = "FILE_SIZE";
diff --git a/common/constants.h b/common/constants.h
index eb489fc..7170201 100644
--- a/common/constants.h
+++ b/common/constants.h
@@ -104,6 +104,7 @@
 extern const char kPrefsVerityWritten[];
 extern const char kPrefsWallClockScatteringWaitPeriod[];
 extern const char kPrefsWallClockStagingWaitPeriod[];
+extern const char kPrefsManifestBytes[];
 
 // Keys used when storing and loading payload properties.
 extern const char kPayloadPropertyFileSize[];