diff --git a/cspell.json b/cspell.json
index 1b5ac0f836b..a5da57d76e0 100644
--- a/cspell.json
+++ b/cspell.json
@@ -41,6 +41,8 @@
         "dryrun",
         "EBUSY",
         "encryptors",
+        "ESECMK",
+        "ESEKEK",
         "evictable",
         "FCBIS",
         "fromjson",
@@ -55,6 +57,7 @@
         "journaled",
         "journaling",
         "jstests",
+        "KEKID",
         "killable",
         "kmip",
         "logd",
@@ -88,6 +91,7 @@
         "shardsvr",
         "sizeStorer",
         "sleepmillis",
+        "SLSKEK",
         "srcs",
         "starlark",
         "stdx",
diff --git a/src/mongo/db/server_feature_flags.idl b/src/mongo/db/server_feature_flags.idl
index fcf6fbc776c..a1ea5e62a05 100644
--- a/src/mongo/db/server_feature_flags.idl
+++ b/src/mongo/db/server_feature_flags.idl
@@ -296,6 +296,11 @@ feature_flags:
         cpp_varname: gFeatureFlagQEPrefixSuffixSearch
         default: false
         fcv_gated: true
+    featureFlagIncludeDeltaHeaderForPhylog:
+        description: "Enable including delta headers for phylog pages."
+        cpp_varname: gFeatureFlagIncludeDeltaHeaderForPhylog
+        default: false
+        fcv_gated: false
 
 server_parameters:
     allowDirectSystemBucketsAccess: