diff --git a/builtin/multi-pack-index.c b/builtin/multi-pack-index.c
index 5f364aa816..3fcb207f1a 100644
--- a/builtin/multi-pack-index.c
+++ b/builtin/multi-pack-index.c
@@ -9,6 +9,7 @@
 #include "strbuf.h"
 #include "trace2.h"
 #include "odb.h"
+#include "odb/source.h"
 #include "replace-object.h"
 #include "repository.h"
 
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 143f7cb3cc..4957487536 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -29,6 +29,7 @@
 #include "object-file.h"
 #include "object-name.h"
 #include "odb.h"
+#include "odb/source.h"
 #include "advice.h"
 #include "branch.h"
 #include "list-objects-filter-options.h"
diff --git a/odb.h b/odb.h
index 86e0365c24..7a583e3873 100644
--- a/odb.h
+++ b/odb.h
@@ -3,7 +3,6 @@
 
 #include "hashmap.h"
 #include "object.h"
-#include "odb/source.h"
 #include "oidset.h"
 #include "oidmap.h"
 #include "string-list.h"
@@ -12,6 +11,7 @@
 struct oidmap;
 struct oidtree;
 struct strbuf;
+struct strvec;
 struct repository;
 struct multi_pack_index;
 
@@ -339,6 +339,42 @@ struct object_info {
  */
 #define OBJECT_INFO_INIT { 0 }
 
+/* Flags that can be passed to `odb_read_object_info_extended()`. */
+enum object_info_flags {
+	/* Invoke lookup_replace_object() on the given hash. */
+	OBJECT_INFO_LOOKUP_REPLACE = (1 << 0),
+
+	/* Do not reprepare object sources when the first lookup has failed. */
+	OBJECT_INFO_QUICK = (1 << 1),
+
+	/*
+	 * Do not attempt to fetch the object if missing (even if fetch_is_missing is
+	 * nonzero).
+	 */
+	OBJECT_INFO_SKIP_FETCH_OBJECT = (1 << 2),
+
+	/* Die if object corruption (not just an object being missing) was detected. */
+	OBJECT_INFO_DIE_IF_CORRUPT = (1 << 3),
+
+	/*
+	 * We have already tried reading the object, but it couldn't be found
+	 * via any of the attached sources, and are now doing a second read.
+	 * This second read asks the individual sources to also evaluate
+	 * whether any on-disk state may have changed that may have caused the
+	 * object to appear.
+	 *
+	 * This flag is for internal use, only. The second read only occurs
+	 * when `OBJECT_INFO_QUICK` was not passed.
+	 */
+	OBJECT_INFO_SECOND_READ = (1 << 4),
+
+	/*
+	 * This is meant for bulk prefetching of missing blobs in a partial
+	 * clone. Implies OBJECT_INFO_SKIP_FETCH_OBJECT and OBJECT_INFO_QUICK.
+	 */
+	OBJECT_INFO_FOR_PREFETCH = (OBJECT_INFO_SKIP_FETCH_OBJECT | OBJECT_INFO_QUICK),
+};
+
 /*
  * Read object info from the object database and populate the `object_info`
  * structure. Returns 0 on success, a negative error code otherwise.
@@ -432,6 +468,18 @@ enum odb_for_each_object_flags {
 	ODB_FOR_EACH_OBJECT_SKIP_ON_DISK_KEPT_PACKS = (1<<4),
 };
 
+/*
+ * A callback function that can be used to iterate through objects. If given,
+ * the optional `oi` parameter will be populated the same as if you would call
+ * `odb_read_object_info()`.
+ *
+ * Returning a non-zero error code will cause iteration to abort. The error
+ * code will be propagated.
+ */
+typedef int (*odb_for_each_object_cb)(const struct object_id *oid,
+				      struct object_info *oi,
+				      void *cb_data);
+
 /*
  * Iterate through all objects contained in the object database. Note that
  * objects may be iterated over multiple times in case they are either stored
diff --git a/odb/source.h b/odb/source.h
index caac558149..a1fd9dd920 100644
--- a/odb/source.h
+++ b/odb/source.h
@@ -2,6 +2,7 @@
 #define ODB_SOURCE_H
 
 #include "object.h"
+#include "odb.h"
 
 enum odb_source_type {
 	/*
@@ -14,61 +15,10 @@ enum odb_source_type {
 	ODB_SOURCE_FILES,
 };
 
-/* Flags that can be passed to `odb_read_object_info_extended()`. */
-enum object_info_flags {
-	/* Invoke lookup_replace_object() on the given hash. */
-	OBJECT_INFO_LOOKUP_REPLACE = (1 << 0),
-
-	/* Do not reprepare object sources when the first lookup has failed. */
-	OBJECT_INFO_QUICK = (1 << 1),
-
-	/*
-	 * Do not attempt to fetch the object if missing (even if fetch_is_missing is
-	 * nonzero).
-	 */
-	OBJECT_INFO_SKIP_FETCH_OBJECT = (1 << 2),
-
-	/* Die if object corruption (not just an object being missing) was detected. */
-	OBJECT_INFO_DIE_IF_CORRUPT = (1 << 3),
-
-	/*
-	 * We have already tried reading the object, but it couldn't be found
-	 * via any of the attached sources, and are now doing a second read.
-	 * This second read asks the individual sources to also evaluate
-	 * whether any on-disk state may have changed that may have caused the
-	 * object to appear.
-	 *
-	 * This flag is for internal use, only. The second read only occurs
-	 * when `OBJECT_INFO_QUICK` was not passed.
-	 */
-	OBJECT_INFO_SECOND_READ = (1 << 4),
-
-	/*
-	 * This is meant for bulk prefetching of missing blobs in a partial
-	 * clone. Implies OBJECT_INFO_SKIP_FETCH_OBJECT and OBJECT_INFO_QUICK.
-	 */
-	OBJECT_INFO_FOR_PREFETCH = (OBJECT_INFO_SKIP_FETCH_OBJECT | OBJECT_INFO_QUICK),
-};
-
 struct object_id;
-struct object_info;
 struct odb_read_stream;
-struct odb_transaction;
-struct odb_write_stream;
 struct strvec;
 
-/*
- * A callback function that can be used to iterate through objects. If given,
- * the optional `oi` parameter will be populated the same as if you would call
- * `odb_read_object_info()`.
- *
- * Returning a non-zero error code will cause iteration to abort. The error
- * code will be propagated.
- */
-typedef int (*odb_for_each_object_cb)(const struct object_id *oid,
-				      struct object_info *oi,
-				      void *cb_data);
-
 /*
  * The source is the part of the object database that stores the actual
  * objects. It thus encapsulates the logic to read and write the specific
diff --git a/odb/streaming.c b/odb/streaming.c
index a4355cd245..5927a12954 100644
--- a/odb/streaming.c
+++ b/odb/streaming.c
@@ -7,6 +7,7 @@
 #include "environment.h"
 #include "repository.h"
 #include "odb.h"
+#include "odb/source.h"
 #include "odb/streaming.h"
 #include "replace-object.h"
 
diff --git a/repository.c b/repository.c
index e7fa42c14f..05c26bdbc3 100644
--- a/repository.c
+++ b/repository.c
@@ -2,6 +2,7 @@
 #include "abspath.h"
 #include "repository.h"
 #include "odb.h"
+#include "odb/source.h"
 #include "config.h"
 #include "object.h"
 #include "lockfile.h"
diff --git a/submodule-config.c b/submodule-config.c
index 1f19fe2077..72a46b7a54 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -14,6 +14,7 @@
 #include "strbuf.h"
 #include "object-name.h"
 #include "odb.h"
+#include "odb/source.h"
 #include "parse-options.h"
 #include "thread-utils.h"
 #include "tree-walk.h"
diff --git a/tmp-objdir.c b/tmp-objdir.c
index e436eed07e..d199d39e7c 100644
--- a/tmp-objdir.c
+++ b/tmp-objdir.c
@@ -11,6 +11,7 @@
 #include "strvec.h"
 #include "quote.h"
 #include "odb.h"
+#include "odb/source.h"
 #include "repository.h"
 
 struct tmp_objdir {