diff --git a/cli.ts b/cli.ts
index a0a25215..365ad6d3 100644
--- a/cli.ts
+++ b/cli.ts
@@ -4,8 +4,9 @@ import { parse as parseJsonc } from "./lib/std/jsonc.ts";
 import { dirname, extname, join } from "./lib/std/path.ts";
 import { colors, Command, List, Select } from "./lib/x/cliffy.ts";
 import { URI } from "./lib/uri.ts";
-import { DependencyUpdate, FileUpdate } from "./mod.ts";
-import { commitAll } from "./git.ts";
+import { DependencyUpdate } from "./lib/update.ts";
+import { FileUpdate } from "./lib/file.ts";
+import { commitAll } from "./lib/git.ts";
 
 const { gray, yellow, bold } = colors;
 
diff --git a/git.ts b/git.ts
index e1f21cf9..40cad92f 100644
--- a/git.ts
+++ b/git.ts
@@ -23,4 +23,4 @@
  * @module
  */
 
-export * from "./src/git.ts";
+export * from "./lib/git.ts";
diff --git a/src/dependency.ts b/lib/dependency.ts
similarity index 94%
rename from src/dependency.ts
rename to lib/dependency.ts
index 3cec507c..54af8f87 100644
--- a/src/dependency.ts
+++ b/lib/dependency.ts
@@ -1,8 +1,7 @@
-import type { Maybe } from "../lib/types.ts";
-import { Mutex } from "../lib/x/async.ts";
-import type { Path, SemVerString } from "./types.ts";
+import { assertExists } from "./std/assert.ts";
+import { Mutex } from "./x/async.ts";
+import type { Maybe, Path, SemVerString } from "./types.ts";
 import { parseSemVer } from "./semver.ts";
-import { assertExists } from "../lib/std/assert.ts";
 
 export interface Dependency {
   name: string;
diff --git a/src/dependency_test.ts b/lib/dependency_test.ts
similarity index 90%
rename from src/dependency_test.ts
rename to lib/dependency_test.ts
index dae9897f..56a1a1b8 100644
--- a/src/dependency_test.ts
+++ b/lib/dependency_test.ts
@@ -1,5 +1,5 @@
-import { describe, it } from "../lib/std/testing.ts";
-import { assertEquals } from "../lib/std/assert.ts";
+import { describe, it } from "./std/testing.ts";
+import { assertEquals } from "./std/assert.ts";
 import { Dependency } from "./dependency.ts";
 
 describe("parseProps()", () => {
diff --git a/src/file.ts b/lib/file.ts
similarity index 97%
rename from src/file.ts
rename to lib/file.ts
index b4a8a6f6..c0ba3250 100644
--- a/src/file.ts
+++ b/lib/file.ts
@@ -1,5 +1,5 @@
 import { DependencyUpdate } from "./update.ts";
-import { URI } from "../lib/uri.ts";
+import { URI } from "./uri.ts";
 
 export interface FileUpdate {
   /** The specifier of the updated dependency (a remote module.) */
diff --git a/src/file_test.ts b/lib/file_test.ts
similarity index 96%
rename from src/file_test.ts
rename to lib/file_test.ts
index 6077e91f..f865f751 100644
--- a/src/file_test.ts
+++ b/lib/file_test.ts
@@ -5,15 +5,15 @@ import {
   it,
   type Stub,
   stub,
-} from "../lib/std/testing.ts";
+} from "./std/testing.ts";
 import {
   assertArrayIncludes,
   assertEquals,
   assertExists,
-} from "../lib/std/assert.ts";
+} from "./std/assert.ts";
 import { DependencyUpdate } from "./update.ts";
 import { FileUpdate } from "./file.ts";
-import { URI } from "../lib/uri.ts";
+import { URI } from "./uri.ts";
 
 describe("collect", () => {
   it("direct import", async () => {
diff --git a/src/git.ts b/lib/git.ts
similarity index 98%
rename from src/git.ts
rename to lib/git.ts
index 55714b8c..8c8f7244 100644
--- a/src/git.ts
+++ b/lib/git.ts
@@ -1,7 +1,7 @@
 import { DependencyUpdate } from "./update.ts";
 import { FileUpdate } from "./file.ts";
 import { createVersionProp, type VersionProp } from "./versions.ts";
-import { URI } from "../lib/uri.ts";
+import { URI } from "./uri.ts";
 
 export interface CommitProps {
   /** The name of the module group */
diff --git a/src/git_test.ts b/lib/git_test.ts
similarity index 96%
rename from src/git_test.ts
rename to lib/git_test.ts
index 74cae21f..55903224 100644
--- a/src/git_test.ts
+++ b/lib/git_test.ts
@@ -1,5 +1,4 @@
 // deno-lint-ignore-file no-explicit-any
-
 import {
   afterAll,
   afterEach,
@@ -9,9 +8,9 @@ import {
   it,
   type Stub,
   stub,
-} from "../lib/std/testing.ts";
-import { assertArrayIncludes, assertEquals } from "../lib/std/assert.ts";
-import { URI } from "../lib/uri.ts";
+} from "./std/testing.ts";
+import { assertArrayIncludes, assertEquals } from "./std/assert.ts";
+import { URI } from "./uri.ts";
 import { DependencyUpdate } from "./update.ts";
 import { commitAll } from "./git.ts";
 
diff --git a/src/import_map.ts b/lib/import_map.ts
similarity index 87%
rename from src/import_map.ts
rename to lib/import_map.ts
index 54697f2a..70e30bd2 100644
--- a/src/import_map.ts
+++ b/lib/import_map.ts
@@ -1,9 +1,9 @@
-import { maxBy } from "../lib/std/collections.ts";
-import { parse as parseJsonc } from "../lib/std/jsonc.ts";
-import { type ImportMapJson, parseFromJson } from "../lib/x/import_map.ts";
-import { is } from "../lib/x/unknownutil.ts";
-import type { Maybe } from "../lib/types.ts";
-import { URI } from "../lib/uri.ts";
+import { maxBy } from "./std/collections.ts";
+import { parse as parseJsonc } from "./std/jsonc.ts";
+import { type ImportMapJson, parseFromJson } from "./x/import_map.ts";
+import { is } from "./x/unknownutil.ts";
+import type { Maybe } from "./types.ts";
+import { URI } from "./uri.ts";
 import { URIScheme } from "./types.ts";
 
 export type { ImportMapJson };
diff --git a/src/import_map_test.ts b/lib/import_map_test.ts
similarity index 95%
rename from src/import_map_test.ts
rename to lib/import_map_test.ts
index 57bbed7f..b711c555 100644
--- a/src/import_map_test.ts
+++ b/lib/import_map_test.ts
@@ -1,6 +1,6 @@
-import { beforeAll, describe, it } from "../lib/std/testing.ts";
-import { assertEquals, assertExists } from "../lib/std/assert.ts";
-import { URI } from "../lib/uri.ts";
+import { beforeAll, describe, it } from "./std/testing.ts";
+import { assertEquals, assertExists } from "./std/assert.ts";
+import { URI } from "./uri.ts";
 import { ImportMap } from "./import_map.ts";
 
 describe("readFromJson()", () => {
diff --git a/src/loader.ts b/lib/loader.ts
similarity index 94%
rename from src/loader.ts
rename to lib/loader.ts
index 26968c46..27005e87 100644
--- a/src/loader.ts
+++ b/lib/loader.ts
@@ -1,7 +1,7 @@
 import {
   type CreateGraphOptions,
   load as defaultLoad,
-} from "../lib/x/deno_graph.ts";
+} from "./x/deno_graph.ts";
 
 export const load: NonNullable<CreateGraphOptions["load"]> = async (
   specifier,
diff --git a/src/semver.ts b/lib/semver.ts
similarity index 87%
rename from src/semver.ts
rename to lib/semver.ts
index 83a4b367..5d32f9cc 100644
--- a/src/semver.ts
+++ b/lib/semver.ts
@@ -1,5 +1,4 @@
-import type { Maybe } from "../lib/types.ts";
-import type { SemVerString } from "./types.ts";
+import type { Maybe, SemVerString } from "./types.ts";
 
 // Ref: https://semver.org/#is-there-a-suggested-regular-expression-regex-to-check-a-semver-string
 const SEMVER_REGEXP =
diff --git a/src/semver_test.ts b/lib/semver_test.ts
similarity index 76%
rename from src/semver_test.ts
rename to lib/semver_test.ts
index c1e9b88b..609c8b27 100644
--- a/src/semver_test.ts
+++ b/lib/semver_test.ts
@@ -1,5 +1,5 @@
-import { describe, it } from "../lib/std/testing.ts";
-import { assertEquals } from "../lib/std/assert.ts";
+import { describe, it } from "./std/testing.ts";
+import { assertEquals } from "./std/assert.ts";
 import { parseSemVer } from "./semver.ts";
 
 describe("parseSemVer", () => {
diff --git a/lib/types.ts b/lib/types.ts
index d3d5f6c2..ef4dfbb8 100644
--- a/lib/types.ts
+++ b/lib/types.ts
@@ -1,2 +1,14 @@
 export type Maybe<T> = T | undefined;
 export type Brand<T, B> = T & { __brand: B };
+
+/** A string that represents a path segment (e.g. `src/lib.ts`.) */
+export type Path = Brand<string, "Path">;
+
+/** A string that represents a semver (e.g. `v1.0.0`.) */
+export type SemVerString = Brand<string, "SemVerString">;
+
+const URI_SCHEMES = ["http", "https", "file", "npm", "node"] as const;
+export type URIScheme = typeof URI_SCHEMES[number];
+export const URIScheme = {
+  values: URI_SCHEMES,
+};
diff --git a/src/update.ts b/lib/update.ts
similarity index 98%
rename from src/update.ts
rename to lib/update.ts
index 7780f0a0..b26d774d 100644
--- a/src/update.ts
+++ b/lib/update.ts
@@ -2,8 +2,8 @@ import {
   createGraph,
   init as initDenoGraph,
   type ModuleJson,
-} from "../lib/x/deno_graph.ts";
-import { RelativePath, URI } from "../lib/uri.ts";
+} from "./x/deno_graph.ts";
+import { RelativePath, URI } from "./uri.ts";
 import type { SemVerString } from "./types.ts";
 import { ImportMap, ImportMapJson } from "./import_map.ts";
 import { Dependency } from "./dependency.ts";
diff --git a/src/update_test.ts b/lib/update_test.ts
similarity index 97%
rename from src/update_test.ts
rename to lib/update_test.ts
index 09cbf842..eaf42e18 100644
--- a/src/update_test.ts
+++ b/lib/update_test.ts
@@ -1,11 +1,11 @@
-import { beforeAll, describe, it } from "../lib/std/testing.ts";
+import { beforeAll, describe, it } from "./std/testing.ts";
 import {
   assertEquals,
   assertExists,
   assertNotEquals,
   assertObjectMatch,
-} from "../lib/std/assert.ts";
-import { URI } from "../lib/uri.ts";
+} from "./std/assert.ts";
+import { URI } from "./uri.ts";
 import { _create, DependencyUpdate } from "./update.ts";
 import { ImportMap } from "./import_map.ts";
 
diff --git a/src/versions.ts b/lib/versions.ts
similarity index 83%
rename from src/versions.ts
rename to lib/versions.ts
index 5d0a7429..cc31f0ab 100644
--- a/src/versions.ts
+++ b/lib/versions.ts
@@ -1,8 +1,8 @@
 // Copyright 2023 Shun Ueda. All rights reserved. MIT license.
 
-import type { Maybe } from "../lib/types.ts";
-import { distinct } from "../lib/std/collections.ts";
-import { DependencyUpdate } from "../mod.ts";
+import type { Maybe } from "./types.ts";
+import { distinct } from "./std/collections.ts";
+import { DependencyUpdate } from "./update.ts";
 
 export type VersionProp = {
   from?: string;
diff --git a/src/versions_test.ts b/lib/versions_test.ts
similarity index 91%
rename from src/versions_test.ts
rename to lib/versions_test.ts
index 5ffdd83a..03061cc3 100644
--- a/src/versions_test.ts
+++ b/lib/versions_test.ts
@@ -1,8 +1,8 @@
 // deno-lint-ignore-file no-explicit-any
 
-import { describe, it } from "../lib/std/testing.ts";
-import { assertEquals, assertThrows } from "../lib/std/assert.ts";
-import { createVersionProp } from "../src/versions.ts";
+import { describe, it } from "./std/testing.ts";
+import { assertEquals, assertThrows } from "./std/assert.ts";
+import { createVersionProp } from "./versions.ts";
 
 describe("createVersionProps()", () => {
   it("single version", () => {
diff --git a/src/types.ts b/src/types.ts
deleted file mode 100644
index c68cb913..00000000
--- a/src/types.ts
+++ /dev/null
@@ -1,13 +0,0 @@
-import { Brand } from "../lib/types.ts";
-
-/** A string that represents a path segment (e.g. `src/lib.ts`.) */
-export type Path = Brand<string, "Path">;
-
-/** A string that represents a semver (e.g. `v1.0.0`.) */
-export type SemVerString = Brand<string, "SemVerString">;
-
-const URI_SCHEMES = ["http", "https", "file", "npm", "node"] as const;
-export type URIScheme = typeof URI_SCHEMES[number];
-export const URIScheme = {
-  values: URI_SCHEMES,
-};