diff --git a/java/arcs/core/crdt/CrdtEntity.kt b/java/arcs/core/crdt/CrdtEntity.kt
index 077637480bc..225a137e530 100644
--- a/java/arcs/core/crdt/CrdtEntity.kt
+++ b/java/arcs/core/crdt/CrdtEntity.kt
@@ -427,3 +427,9 @@ class CrdtEntity(
     ) : Operation(actor, versionMap)
   }
 }
+
+/** Converts the [RawEntity] into a [CrdtEntity.Data] model, at the given version. */
+fun RawEntity.toCrdtEntityData(
+  versionMap: VersionMap,
+  referenceBuilder: (Referencable) -> CrdtEntity.Reference = { CrdtEntity.ReferenceImpl(it.id) }
+): CrdtEntity.Data = CrdtEntity.Data(versionMap.copy(), this, referenceBuilder)
diff --git a/java/arcs/core/crdt/extension/BUILD b/java/arcs/core/crdt/extension/BUILD
deleted file mode 100644
index 6283ec5da11..00000000000
--- a/java/arcs/core/crdt/extension/BUILD
+++ /dev/null
@@ -1,21 +0,0 @@
-load(
-    "//third_party/java/arcs/build_defs:build_defs.bzl",
-    "arcs_kt_library",
-)
-
-licenses(["notice"])
-
-package(default_visibility = ["//java/arcs:allowed-packages"])
-
-arcs_kt_library(
-    name = "extension",
-    srcs = glob(["*.kt"]),
-    deps = [
-        "//java/arcs/core/common",
-        "//java/arcs/core/crdt",
-        "//java/arcs/core/data",
-        "//java/arcs/core/data:rawentity",
-        "//java/arcs/core/data/util:data-util",
-        "//java/arcs/core/util",
-    ],
-)
diff --git a/java/arcs/core/crdt/extension/ConversionExtensions.kt b/java/arcs/core/crdt/extension/ConversionExtensions.kt
deleted file mode 100644
index 34d4cf59f17..00000000000
--- a/java/arcs/core/crdt/extension/ConversionExtensions.kt
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Copyright 2020 Google LLC.
- *
- * This code may only be used under the BSD style license found at
- * http://polymer.github.io/LICENSE.txt
- *
- * Code distributed by Google as part of this project is also subject to an additional IP rights
- * grant found at
- * http://polymer.github.io/PATENTS.txt
- */
-
-package arcs.core.crdt.extension
-
-import arcs.core.common.Referencable
-import arcs.core.crdt.CrdtEntity
-import arcs.core.crdt.VersionMap
-import arcs.core.data.RawEntity
-import arcs.core.data.util.ReferencablePrimitive
-import arcs.core.util.Base64
-
-/** Converts the [RawEntity] into a [CrdtEntity.Data] model, at the given version. */
-fun RawEntity.toCrdtEntityData(
-  versionMap: VersionMap,
-  referenceBuilder: (Referencable) -> CrdtEntity.Reference = { CrdtEntity.ReferenceImpl(it.id) }
-): CrdtEntity.Data = CrdtEntity.Data(versionMap.copy(), this, referenceBuilder)
-
-private fun Any?.toReferencable(): Referencable {
-  requireNotNull(this) { "Cannot create a referencable from a null value." }
-  return when {
-    ReferencablePrimitive.isSupportedPrimitive(this::class) -> {
-      if (this is ByteArray) {
-        ReferencablePrimitive(
-          ByteArray::class,
-          this,
-          valueRepr = Base64.encode(this)
-        )
-      } else {
-        ReferencablePrimitive(this::class, this)
-      }
-    }
-    this is Referencable -> this
-    else -> throw IllegalArgumentException(
-      "Entity contains non-referencable non-primitive values."
-    )
-  }
-}
diff --git a/java/arcs/core/storage/driver/BUILD b/java/arcs/core/storage/driver/BUILD
index c7ab64bf522..59b788ac978 100644
--- a/java/arcs/core/storage/driver/BUILD
+++ b/java/arcs/core/storage/driver/BUILD
@@ -17,7 +17,6 @@ arcs_kt_library(
         ":ramdisk",
         "//java/arcs/core/common",
         "//java/arcs/core/crdt",
-        "//java/arcs/core/crdt/extension",
         "//java/arcs/core/data",
         "//java/arcs/core/data:rawentity",
         "//java/arcs/core/data/util:data-util",
@@ -28,11 +27,9 @@ arcs_kt_library(
         "//java/arcs/core/storage/driver/volatiles",
         "//java/arcs/core/storage/driver/volatiles:volatile_impl",
         "//java/arcs/core/storage/keys",
-        "//java/arcs/core/storage/referencemode",
         "//java/arcs/core/type",
         "//java/arcs/core/util",
         "//third_party/java/androidx/annotation",
-        "//third_party/kotlin/kotlinx_atomicfu",
         "//third_party/kotlin/kotlinx_coroutines",
     ],
 )
@@ -56,7 +53,6 @@ arcs_kt_library(
     deps = [
         "//java/arcs/core/common",
         "//java/arcs/core/crdt",
-        "//java/arcs/core/crdt/extension",
         "//java/arcs/core/data",
         "//java/arcs/core/data:rawentity",
         "//java/arcs/core/data/util:data-util",
@@ -67,11 +63,9 @@ arcs_kt_library(
         "//java/arcs/core/storage/driver/volatiles",
         "//java/arcs/core/storage/driver/volatiles:volatile_impl",
         "//java/arcs/core/storage/keys",
-        "//java/arcs/core/storage/referencemode",
         "//java/arcs/core/type",
         "//java/arcs/core/util",
         "//third_party/java/androidx/annotation",
-        "//third_party/kotlin/kotlinx_atomicfu",
         "//third_party/kotlin/kotlinx_coroutines",
     ],
 )
diff --git a/java/arcs/core/storage/driver/Database.kt b/java/arcs/core/storage/driver/Database.kt
index 5cd1c9d9db5..10c80f76754 100644
--- a/java/arcs/core/storage/driver/Database.kt
+++ b/java/arcs/core/storage/driver/Database.kt
@@ -17,7 +17,7 @@ import arcs.core.crdt.CrdtEntity
 import arcs.core.crdt.CrdtSet
 import arcs.core.crdt.CrdtSingleton
 import arcs.core.crdt.VersionMap
-import arcs.core.crdt.extension.toCrdtEntityData
+import arcs.core.crdt.toCrdtEntityData
 import arcs.core.data.RawEntity
 import arcs.core.data.Schema
 import arcs.core.data.util.ReferencableList
diff --git a/javatests/arcs/core/crdt/CrdtEntityTest.kt b/javatests/arcs/core/crdt/CrdtEntityTest.kt
index d5f28d870c6..33db8495024 100644
--- a/javatests/arcs/core/crdt/CrdtEntityTest.kt
+++ b/javatests/arcs/core/crdt/CrdtEntityTest.kt
@@ -18,6 +18,7 @@ import arcs.core.crdt.CrdtEntity.Operation.RemoveFromSet
 import arcs.core.crdt.CrdtEntity.Operation.SetSingleton
 import arcs.core.crdt.CrdtEntity.ReferenceImpl as Reference
 import arcs.core.data.RawEntity
+import arcs.core.data.util.toReferencable
 import com.google.common.truth.Truth.assertThat
 import kotlin.test.assertFailsWith
 import org.junit.Ignore
@@ -470,8 +471,46 @@ class CrdtEntityTest {
     val emptyEntity = CrdtEntity(VersionMap(), emptyRawEntity)
 
     val changes = emptyEntity.merge(entity.data)
-    println(changes)
     assertThat(changes.modelChange.isEmpty()).isFalse()
     assertThat(changes.otherChange.isEmpty()).isTrue()
   }
+
+  @Test
+  fun toCrdtEntityData_empty() {
+    assertThat(RawEntity().toCrdtEntityData(VersionMap())).isEqualTo(CrdtEntity.Data())
+  }
+
+  @Test
+  fun toCrdtEntityData_populated() {
+    val entity = RawEntity(
+      id = "entityId",
+      singletons = mapOf(
+        "txt" to "foo".toReferencable(),
+        "ent" to RawEntity("id1", mapOf("val" to 3.toReferencable()))
+      ),
+      collections = mapOf(
+        "num" to setOf(3.toReferencable(), 7.toReferencable())
+      ),
+      creationTimestamp = 30,
+      expirationTimestamp = 70
+    )
+    val versionMap = VersionMap("me" to 1)
+    val result = entity.toCrdtEntityData(versionMap) { CrdtEntity.ReferenceImpl("#" + it.id) }
+
+    // Constructing the full expected CrdtEntity.Data is cumbersome; just check the fields manually.
+    assertThat(result.id).isEqualTo("entityId")
+    assertThat(result.versionMap).isEqualTo(versionMap)
+    assertThat(result.creationTimestamp).isEqualTo(30)
+    assertThat(result.expirationTimestamp).isEqualTo(70)
+
+    val singletons = result.singletons
+    assertThat(singletons).hasSize(2)
+    assertThat(singletons["txt"]!!.consumerView!!.id).isEqualTo("#Primitive<kotlin.String>(foo)")
+    assertThat(singletons["ent"]!!.consumerView!!.id).isEqualTo("#id1")
+
+    val collections = result.collections
+    assertThat(collections).hasSize(1)
+    assertThat(collections["num"]!!.consumerView.map { it.id })
+      .containsExactly("#Primitive<kotlin.Int>(3)", "#Primitive<kotlin.Int>(7)")
+  }
 }
diff --git a/javatests/arcs/core/storage/driver/BUILD b/javatests/arcs/core/storage/driver/BUILD
index 78c527b65a3..9bbcc42a7ec 100644
--- a/javatests/arcs/core/storage/driver/BUILD
+++ b/javatests/arcs/core/storage/driver/BUILD
@@ -13,7 +13,6 @@ arcs_kt_jvm_test_suite(
     deps = [
         "//java/arcs/core/common",
         "//java/arcs/core/crdt",
-        "//java/arcs/core/crdt/extension",
         "//java/arcs/core/data",
         "//java/arcs/core/data:schema_fields",
         "//java/arcs/core/data/util:data-util",
@@ -26,7 +25,6 @@ arcs_kt_jvm_test_suite(
         "//java/arcs/core/storage/keys",
         "//java/arcs/core/testutil",
         "//java/arcs/core/type",
-        "//java/arcs/core/util",
         "//java/arcs/core/util/testutil",
         "//java/arcs/jvm/storage/database/testutil",
         "//third_party/java/junit:junit-android",
diff --git a/javatests/arcs/core/storage/driver/DatabaseDriverTest.kt b/javatests/arcs/core/storage/driver/DatabaseDriverTest.kt
index 51b1b8dde8a..1a86bab88c6 100644
--- a/javatests/arcs/core/storage/driver/DatabaseDriverTest.kt
+++ b/javatests/arcs/core/storage/driver/DatabaseDriverTest.kt
@@ -16,7 +16,7 @@ import arcs.core.crdt.CrdtEntity.Reference.Companion.buildReference
 import arcs.core.crdt.CrdtSet
 import arcs.core.crdt.CrdtSingleton
 import arcs.core.crdt.VersionMap
-import arcs.core.crdt.extension.toCrdtEntityData
+import arcs.core.crdt.toCrdtEntityData
 import arcs.core.data.FieldType
 import arcs.core.data.RawEntity
 import arcs.core.data.Schema