diff --git a/docs/development/core/server/kibana-plugin-core-server.elasticsearchservicepreboot.config.md b/docs/development/core/server/kibana-plugin-core-server.elasticsearchservicepreboot.config.md
index 897e1617486715..12a32b4544abaf 100644
--- a/docs/development/core/server/kibana-plugin-core-server.elasticsearchservicepreboot.config.md
+++ b/docs/development/core/server/kibana-plugin-core-server.elasticsearchservicepreboot.config.md
@@ -9,7 +9,7 @@ A limited set of Elasticsearch configuration entries.
 <b>Signature:</b>
 
 ```typescript
-readonly config: ElasticsearchConfigPreboot;
+readonly config: Readonly<ElasticsearchConfigPreboot>;
 ```
 
 ## Example
diff --git a/docs/development/core/server/kibana-plugin-core-server.elasticsearchservicepreboot.md b/docs/development/core/server/kibana-plugin-core-server.elasticsearchservicepreboot.md
index 0b5847ec889435..bf458004b488bd 100644
--- a/docs/development/core/server/kibana-plugin-core-server.elasticsearchservicepreboot.md
+++ b/docs/development/core/server/kibana-plugin-core-server.elasticsearchservicepreboot.md
@@ -15,6 +15,6 @@ export interface ElasticsearchServicePreboot
 
 |  Property | Type | Description |
 |  --- | --- | --- |
-|  [config](./kibana-plugin-core-server.elasticsearchservicepreboot.config.md) | <code>ElasticsearchConfigPreboot</code> | A limited set of Elasticsearch configuration entries. |
+|  [config](./kibana-plugin-core-server.elasticsearchservicepreboot.config.md) | <code>Readonly&lt;ElasticsearchConfigPreboot&gt;</code> | A limited set of Elasticsearch configuration entries. |
 |  [createClient](./kibana-plugin-core-server.elasticsearchservicepreboot.createclient.md) | <code>(type: string, clientConfig?: Partial&lt;ElasticsearchClientConfig&gt;) =&gt; ICustomClusterClient</code> | Create application specific Elasticsearch cluster API client with customized config. See [IClusterClient](./kibana-plugin-core-server.iclusterclient.md)<!-- -->. |
 
diff --git a/src/core/server/elasticsearch/types.ts b/src/core/server/elasticsearch/types.ts
index a9e360e733f0da..375c7015b16d79 100644
--- a/src/core/server/elasticsearch/types.ts
+++ b/src/core/server/elasticsearch/types.ts
@@ -31,7 +31,7 @@ export interface ElasticsearchServicePreboot {
    * const { hosts, credentialsSpecified } = core.elasticsearch.config;
    * ```
    */
-  readonly config: ElasticsearchConfigPreboot;
+  readonly config: Readonly<ElasticsearchConfigPreboot>;
 
   /**
    * Create application specific Elasticsearch cluster API client with customized config. See {@link IClusterClient}.
diff --git a/src/core/server/server.api.md b/src/core/server/server.api.md
index 2b265948b6c210..52548c760e30bb 100644
--- a/src/core/server/server.api.md
+++ b/src/core/server/server.api.md
@@ -1000,7 +1000,7 @@ export interface ElasticsearchConfigPreboot {
 
 // @public (undocumented)
 export interface ElasticsearchServicePreboot {
-    readonly config: ElasticsearchConfigPreboot;
+    readonly config: Readonly<ElasticsearchConfigPreboot>;
     readonly createClient: (type: string, clientConfig?: Partial<ElasticsearchClientConfig>) => ICustomClusterClient;
 }
 
diff --git a/src/core/server/ui_settings/base_ui_settings_client.ts b/src/core/server/ui_settings/base_ui_settings_client.ts
new file mode 100644
index 00000000000000..d16524ef4e3431
--- /dev/null
+++ b/src/core/server/ui_settings/base_ui_settings_client.ts
@@ -0,0 +1,93 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { omit } from 'lodash';
+
+import {
+  IUiSettingsClient,
+  UiSettingsParams,
+  PublicUiSettingsParams,
+  UserProvidedValues,
+} from './types';
+import { Logger } from '../logging';
+
+export interface BaseUiSettingsDefaultsClientOptions {
+  overrides?: Record<string, any>;
+  defaults?: Record<string, UiSettingsParams>;
+  log: Logger;
+}
+
+/**
+ * Base implementation of the {@link IUiSettingsClient}.
+ */
+export abstract class BaseUiSettingsClient implements IUiSettingsClient {
+  private readonly defaults: NonNullable<BaseUiSettingsDefaultsClientOptions['defaults']>;
+  private readonly defaultValues: Record<string, unknown>;
+  protected readonly overrides: NonNullable<BaseUiSettingsDefaultsClientOptions['overrides']>;
+  protected readonly log: Logger;
+
+  protected constructor(options: BaseUiSettingsDefaultsClientOptions) {
+    const { defaults = {}, overrides = {}, log } = options;
+    this.log = log;
+    this.overrides = overrides;
+
+    this.defaults = defaults;
+    this.defaultValues = Object.fromEntries(
+      Object.entries(this.defaults).map(([key, { value }]) => [key, value])
+    );
+  }
+
+  getRegistered() {
+    const copiedDefaults: Record<string, PublicUiSettingsParams> = {};
+    for (const [key, value] of Object.entries(this.defaults)) {
+      copiedDefaults[key] = omit(value, 'schema');
+    }
+    return copiedDefaults;
+  }
+
+  async get<T = any>(key: string): Promise<T> {
+    const all = await this.getAll();
+    return all[key] as T;
+  }
+
+  async getAll<T = any>() {
+    const result = { ...this.defaultValues };
+
+    const userProvided = await this.getUserProvided();
+    Object.keys(userProvided).forEach((key) => {
+      if (userProvided[key].userValue !== undefined) {
+        result[key] = userProvided[key].userValue;
+      }
+    });
+
+    return Object.freeze(result) as Record<string, T>;
+  }
+
+  isOverridden(key: string) {
+    return this.overrides.hasOwnProperty(key);
+  }
+
+  isSensitive(key: string): boolean {
+    const definition = this.defaults[key];
+    return !!definition?.sensitive;
+  }
+
+  protected validateKey(key: string, value: unknown) {
+    const definition = this.defaults[key];
+    if (value === null || definition === undefined) return;
+    if (definition.schema) {
+      definition.schema.validate(value, {}, `validation [${key}]`);
+    }
+  }
+
+  abstract getUserProvided<T = any>(): Promise<Record<string, UserProvidedValues<T>>>;
+  abstract setMany(changes: Record<string, any>): Promise<void>;
+  abstract set(key: string, value: any): Promise<void>;
+  abstract remove(key: string): Promise<void>;
+  abstract removeMany(keys: string[]): Promise<void>;
+}
diff --git a/src/core/server/ui_settings/ui_settings_client.ts b/src/core/server/ui_settings/ui_settings_client.ts
index 61a4966348e74f..53ed41a3e12be5 100644
--- a/src/core/server/ui_settings/ui_settings_client.ts
+++ b/src/core/server/ui_settings/ui_settings_client.ts
@@ -6,21 +6,20 @@
  * Side Public License, v 1.
  */
 
-import { omit } from 'lodash';
-
 import { SavedObjectsErrorHelpers } from '../saved_objects';
 import { SavedObjectsClientContract } from '../saved_objects/types';
 import { Logger } from '../logging';
 import { createOrUpgradeSavedConfig } from './create_or_upgrade_saved_config';
-import { IUiSettingsClient, UiSettingsParams, PublicUiSettingsParams } from './types';
+import { UiSettingsParams } from './types';
 import { CannotOverrideError } from './ui_settings_errors';
 import { Cache } from './cache';
+import { BaseUiSettingsClient } from './base_ui_settings_client';
 
 export interface UiSettingsServiceOptions {
   type: string;
   id: string;
   buildNum: number;
-  savedObjectsClient?: SavedObjectsClientContract;
+  savedObjectsClient: SavedObjectsClientContract;
   overrides?: Record<string, any>;
   defaults?: Record<string, UiSettingsParams>;
   log: Logger;
@@ -37,67 +36,22 @@ interface UserProvidedValue<T = unknown> {
 
 type UserProvided<T = unknown> = Record<string, UserProvidedValue<T>>;
 
-function assertSavedObjectsClient(
-  savedObjectsClient?: SavedObjectsClientContract
-): asserts savedObjectsClient is SavedObjectsClientContract {
-  if (!savedObjectsClient) {
-    throw new Error('Saved Objects Client is not available.');
-  }
-}
-
-export class UiSettingsClient implements IUiSettingsClient {
+export class UiSettingsClient extends BaseUiSettingsClient {
   private readonly type: UiSettingsServiceOptions['type'];
   private readonly id: UiSettingsServiceOptions['id'];
   private readonly buildNum: UiSettingsServiceOptions['buildNum'];
   private readonly savedObjectsClient: UiSettingsServiceOptions['savedObjectsClient'];
-  private readonly overrides: NonNullable<UiSettingsServiceOptions['overrides']>;
-  private readonly defaults: NonNullable<UiSettingsServiceOptions['defaults']>;
-  private readonly defaultValues: Record<string, unknown>;
-  private readonly log: Logger;
   private readonly cache: Cache;
 
   constructor(options: UiSettingsServiceOptions) {
     const { type, id, buildNum, savedObjectsClient, log, defaults = {}, overrides = {} } = options;
+    super({ overrides, defaults, log });
+
     this.type = type;
     this.id = id;
     this.buildNum = buildNum;
     this.savedObjectsClient = savedObjectsClient;
-    this.overrides = overrides;
-    this.log = log;
     this.cache = new Cache();
-    this.defaults = defaults;
-    const defaultValues: Record<string, unknown> = {};
-    Object.keys(this.defaults).forEach((key) => {
-      defaultValues[key] = this.defaults[key].value;
-    });
-    this.defaultValues = defaultValues;
-  }
-
-  getRegistered() {
-    const copiedDefaults: Record<string, PublicUiSettingsParams> = {};
-    for (const [key, value] of Object.entries(this.defaults)) {
-      copiedDefaults[key] = omit(value, 'schema');
-    }
-    return copiedDefaults;
-  }
-
-  async get<T = any>(key: string): Promise<T> {
-    const all = await this.getAll();
-    return all[key] as T;
-  }
-
-  async getAll<T = any>() {
-    const result = { ...this.defaultValues };
-
-    const userProvided = await this.getUserProvided();
-    Object.keys(userProvided).forEach((key) => {
-      if (userProvided[key].userValue !== undefined) {
-        result[key] = userProvided[key].userValue;
-      }
-    });
-
-    Object.freeze(result);
-    return result as Record<string, T>;
   }
 
   async getUserProvided<T = unknown>(): Promise<UserProvided<T>> {
@@ -142,29 +96,12 @@ export class UiSettingsClient implements IUiSettingsClient {
     await this.setMany(changes);
   }
 
-  isOverridden(key: string) {
-    return this.overrides.hasOwnProperty(key);
-  }
-
-  isSensitive(key: string): boolean {
-    const definition = this.defaults[key];
-    return !!definition?.sensitive;
-  }
-
   private assertUpdateAllowed(key: string) {
     if (this.isOverridden(key)) {
       throw new CannotOverrideError(`Unable to update "${key}" because it is overridden`);
     }
   }
 
-  private validateKey(key: string, value: unknown) {
-    const definition = this.defaults[key];
-    if (value === null || definition === undefined) return;
-    if (definition.schema) {
-      definition.schema.validate(value, {}, `validation [${key}]`);
-    }
-  }
-
   private onWriteHook(changes: Record<string, unknown>) {
     for (const key of Object.keys(changes)) {
       this.assertUpdateAllowed(key);
@@ -201,7 +138,6 @@ export class UiSettingsClient implements IUiSettingsClient {
     changes: Record<string, any>;
     autoCreateOrUpgradeIfMissing?: boolean;
   }) {
-    assertSavedObjectsClient(this.savedObjectsClient);
     try {
       await this.savedObjectsClient.update(this.type, this.id, changes);
     } catch (error) {
@@ -227,7 +163,6 @@ export class UiSettingsClient implements IUiSettingsClient {
   private async read({ autoCreateOrUpgradeIfMissing = true }: ReadOptions = {}): Promise<
     Record<string, any>
   > {
-    assertSavedObjectsClient(this.savedObjectsClient);
     try {
       const resp = await this.savedObjectsClient.get<Record<string, any>>(this.type, this.id);
       return resp.attributes;
@@ -257,7 +192,6 @@ export class UiSettingsClient implements IUiSettingsClient {
   }
 
   private isIgnorableError(error: Error) {
-    assertSavedObjectsClient(this.savedObjectsClient);
     const { isForbiddenError, isEsUnavailableError } = this.savedObjectsClient.errors;
 
     return isForbiddenError(error) || isEsUnavailableError(error);
diff --git a/src/core/server/ui_settings/ui_settings_defaults_client.test.ts b/src/core/server/ui_settings/ui_settings_defaults_client.test.ts
new file mode 100644
index 00000000000000..f3e779034ab4bc
--- /dev/null
+++ b/src/core/server/ui_settings/ui_settings_defaults_client.test.ts
@@ -0,0 +1,188 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import Chance from 'chance';
+import { schema } from '@kbn/config-schema';
+
+import { loggingSystemMock } from '../logging/logging_system.mock';
+
+import { UiSettingsDefaultsClient } from './ui_settings_defaults_client';
+
+const logger = loggingSystemMock.create().get();
+
+const chance = new Chance();
+
+describe('ui settings defaults', () => {
+  afterEach(() => jest.clearAllMocks());
+
+  describe('#getUserProvided()', () => {
+    it('only returns overridden values', async () => {
+      const defaults = { foo: { schema: schema.string(), value: 'default foo' } };
+      const overrides = { bar: 'overridden bar', baz: null };
+
+      const uiSettings = new UiSettingsDefaultsClient({ defaults, overrides, log: logger });
+      await expect(uiSettings.getUserProvided()).resolves.toStrictEqual({
+        bar: { userValue: 'overridden bar', isOverridden: true },
+        baz: { isOverridden: true },
+      });
+    });
+  });
+
+  describe('#getAll()', () => {
+    it('returns defaults and overridden values', async () => {
+      const defaults = {
+        foo: { schema: schema.string(), value: 'default foo' },
+        bar: { schema: schema.string() },
+        baz: { schema: schema.string(), value: 'default baz' },
+      };
+      const overrides = { foo: 'overridden foo', zab: 'overridden zab', baz: null };
+
+      const uiSettings = new UiSettingsDefaultsClient({ defaults, overrides, log: logger });
+
+      await expect(uiSettings.getAll()).resolves.toStrictEqual({
+        foo: 'overridden foo',
+        bar: undefined,
+        baz: 'default baz',
+        zab: 'overridden zab',
+      });
+    });
+
+    it('throws if mutates the result of getAll()', async () => {
+      const defaults = {
+        foo: { schema: schema.string(), value: 'default foo' },
+      };
+      const uiSettings = new UiSettingsDefaultsClient({ defaults, log: logger });
+      const result = await uiSettings.getAll();
+
+      expect(() => {
+        result.foo = 'bar';
+      }).toThrow();
+    });
+  });
+
+  describe('#get()', () => {
+    it('returns the overridden value for an overridden key', async () => {
+      const defaults = {
+        foo: { schema: schema.string(), value: 'default foo' },
+      };
+      const overrides = { foo: 'overridden foo' };
+      const uiSettings = new UiSettingsDefaultsClient({ defaults, overrides, log: logger });
+
+      await expect(uiSettings.get('foo')).resolves.toBe('overridden foo');
+    });
+
+    it('returns the default value for an override with value null', async () => {
+      const defaults = {
+        foo: { schema: schema.string(), value: 'default foo' },
+      };
+      const overrides = { foo: null };
+      const uiSettings = new UiSettingsDefaultsClient({ defaults, overrides, log: logger });
+
+      await expect(uiSettings.get('foo')).resolves.toBe('default foo');
+    });
+
+    it('returns the default value if there is no override', async () => {
+      const defaults = {
+        foo: { schema: schema.string(), value: 'default foo' },
+      };
+      const overrides = {};
+      const uiSettings = new UiSettingsDefaultsClient({ defaults, overrides, log: logger });
+
+      await expect(uiSettings.get('foo')).resolves.toBe('default foo');
+    });
+  });
+
+  describe('#setMany()', () => {
+    it('does not throw', async () => {
+      const uiSettings = new UiSettingsDefaultsClient({ log: logger });
+      await expect(uiSettings.setMany()).resolves.not.toThrow();
+    });
+  });
+
+  describe('#set()', () => {
+    it('does not throw', async () => {
+      const uiSettings = new UiSettingsDefaultsClient({ log: logger });
+      await expect(uiSettings.set()).resolves.not.toThrow();
+    });
+  });
+
+  describe('#remove()', () => {
+    it('does not throw', async () => {
+      const uiSettings = new UiSettingsDefaultsClient({ log: logger });
+      await expect(uiSettings.remove()).resolves.not.toThrow();
+    });
+  });
+
+  describe('#removeMany()', () => {
+    it('does not throw', async () => {
+      const uiSettings = new UiSettingsDefaultsClient({ log: logger });
+      await expect(uiSettings.removeMany()).resolves.not.toThrow();
+    });
+  });
+
+  describe('#getRegistered()', () => {
+    it('returns the registered settings passed to the constructor and does not leak validation schema outside', () => {
+      const value = chance.word();
+      const defaults = { key: { schema: schema.string(), value } };
+      const uiSettings = new UiSettingsDefaultsClient({ defaults, log: logger });
+      expect(uiSettings.getRegistered()).toStrictEqual({ key: { value } });
+    });
+  });
+
+  describe('#isSensitive()', () => {
+    it('returns false if sensitive config is not set', () => {
+      const defaults = { foo: { schema: schema.string(), value: '1' } };
+
+      const uiSettings = new UiSettingsDefaultsClient({ defaults, log: logger });
+      expect(uiSettings.isSensitive('foo')).toBe(false);
+    });
+
+    it('returns false if key is not in the settings', () => {
+      const uiSettings = new UiSettingsDefaultsClient({ log: logger });
+      expect(uiSettings.isSensitive('baz')).toBe(false);
+    });
+
+    it('returns true if `sensitive` is set', () => {
+      const defaults = { foo: { schema: schema.string(), sensitive: true, value: '1' } };
+
+      const uiSettings = new UiSettingsDefaultsClient({ defaults, log: logger });
+      expect(uiSettings.isSensitive('foo')).toBe(true);
+    });
+  });
+
+  describe('#isOverridden()', () => {
+    it('returns false if no overrides defined', () => {
+      const uiSettings = new UiSettingsDefaultsClient({ log: logger });
+      expect(uiSettings.isOverridden('foo')).toBe(false);
+    });
+
+    it('returns false if overrides defined but key is not included', () => {
+      const uiSettings = new UiSettingsDefaultsClient({
+        overrides: { foo: true, bar: true },
+        log: logger,
+      });
+      expect(uiSettings.isOverridden('baz')).toBe(false);
+    });
+
+    it('returns false for object prototype properties', () => {
+      const uiSettings = new UiSettingsDefaultsClient({
+        overrides: { foo: true, bar: true },
+        log: logger,
+      });
+      expect(uiSettings.isOverridden('hasOwnProperty')).toBe(false);
+    });
+
+    it('returns true if overrides defined and key is overridden', () => {
+      const uiSettings = new UiSettingsDefaultsClient({
+        overrides: { foo: true, bar: true },
+        log: logger,
+      });
+      expect(uiSettings.isOverridden('bar')).toBe(true);
+    });
+  });
+});
diff --git a/src/core/server/ui_settings/ui_settings_defaults_client.ts b/src/core/server/ui_settings/ui_settings_defaults_client.ts
new file mode 100644
index 00000000000000..fad90b9b0eaeed
--- /dev/null
+++ b/src/core/server/ui_settings/ui_settings_defaults_client.ts
@@ -0,0 +1,58 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import { UiSettingsParams, UserProvidedValues } from './types';
+import { Logger } from '../logging';
+import { BaseUiSettingsClient } from './base_ui_settings_client';
+
+export interface UiSettingsDefaultsClientOptions {
+  overrides?: Record<string, any>;
+  defaults?: Record<string, UiSettingsParams>;
+  log: Logger;
+}
+
+/**
+ * Implementation of the {@link IUiSettingsClient} that only gives a read-only access to the default UI Settings values and any overrides.
+ */
+export class UiSettingsDefaultsClient extends BaseUiSettingsClient {
+  private readonly userProvided: Record<string, UserProvidedValues<unknown>>;
+
+  constructor(options: UiSettingsDefaultsClientOptions) {
+    super(options);
+
+    // The only "userProvided" settings `UiSettingsDefaultsClient` is aware about are explicit overrides.
+    this.userProvided = Object.fromEntries(
+      Object.entries(this.overrides).map(([key, value]) => [
+        key,
+        // Dropping the userValue if override is null
+        value === null ? { isOverridden: true } : { isOverridden: true, userValue: value },
+      ])
+    );
+  }
+
+  async getUserProvided<T = unknown>(): Promise<Record<string, UserProvidedValues<T>>> {
+    return this.userProvided as Record<string, UserProvidedValues<T>>;
+  }
+
+  // Any mutating operations are not supported by default UI settings.
+  async setMany() {
+    this.log.warn('`setMany` operation is not supported.');
+  }
+
+  async set() {
+    this.log.warn('`set` operation is not supported.');
+  }
+
+  async remove() {
+    this.log.warn('`remove` operation is not supported.');
+  }
+
+  async removeMany() {
+    this.log.warn('`removeMany` operation is not supported.');
+  }
+}
diff --git a/src/core/server/ui_settings/ui_settings_service.test.mock.ts b/src/core/server/ui_settings/ui_settings_service.test.mock.ts
index afe8b401877bca..aae25563c2b887 100644
--- a/src/core/server/ui_settings/ui_settings_service.test.mock.ts
+++ b/src/core/server/ui_settings/ui_settings_service.test.mock.ts
@@ -11,6 +11,11 @@ jest.doMock('./ui_settings_client', () => ({
   UiSettingsClient: MockUiSettingsClientConstructor,
 }));
 
+export const MockUiSettingsDefaultsClientConstructor = jest.fn();
+jest.doMock('./ui_settings_defaults_client', () => ({
+  UiSettingsDefaultsClient: MockUiSettingsDefaultsClientConstructor,
+}));
+
 export const getCoreSettingsMock = jest.fn();
 jest.doMock('./settings', () => ({
   getCoreSettings: getCoreSettingsMock,
diff --git a/src/core/server/ui_settings/ui_settings_service.test.ts b/src/core/server/ui_settings/ui_settings_service.test.ts
index 7f2423c9798a7e..b829f62d2263d7 100644
--- a/src/core/server/ui_settings/ui_settings_service.test.ts
+++ b/src/core/server/ui_settings/ui_settings_service.test.ts
@@ -11,6 +11,7 @@ import { schema } from '@kbn/config-schema';
 
 import {
   MockUiSettingsClientConstructor,
+  MockUiSettingsDefaultsClientConstructor,
   getCoreSettingsMock,
 } from './ui_settings_service.test.mock';
 import { UiSettingsService, SetupDeps } from './ui_settings_service';
@@ -19,7 +20,7 @@ import { savedObjectsClientMock } from '../mocks';
 import { savedObjectsServiceMock } from '../saved_objects/saved_objects_service.mock';
 import { mockCoreContext } from '../core_context.mock';
 import { uiSettingsType } from './saved_objects';
-import { UiSettingsClient } from './ui_settings_client';
+import { UiSettingsDefaultsClient } from './ui_settings_defaults_client';
 
 const overrides = {
   overrideBaz: 'baz',
@@ -65,11 +66,11 @@ describe('uiSettings', () => {
       const { createDefaultsClient } = await service.preboot();
 
       const client = createDefaultsClient();
-      expect(client).toBeInstanceOf(UiSettingsClient);
+      expect(client).toBeInstanceOf(UiSettingsDefaultsClient);
 
-      expect(MockUiSettingsClientConstructor).toBeCalledTimes(1);
-      const [[constructorArgs]] = MockUiSettingsClientConstructor.mock.calls;
-      expect(constructorArgs).toMatchObject({ type: 'config', overrides, defaults: {} });
+      expect(MockUiSettingsDefaultsClientConstructor).toBeCalledTimes(1);
+      const [[constructorArgs]] = MockUiSettingsDefaultsClientConstructor.mock.calls;
+      expect(constructorArgs).toMatchObject({ overrides, defaults: {} });
       expect(constructorArgs.overrides).toBe(overrides);
     });
   });
diff --git a/src/core/server/ui_settings/ui_settings_service.ts b/src/core/server/ui_settings/ui_settings_service.ts
index 5d7073487a72b5..d011b6e21907fe 100644
--- a/src/core/server/ui_settings/ui_settings_service.ts
+++ b/src/core/server/ui_settings/ui_settings_service.ts
@@ -27,6 +27,7 @@ import {
 import { uiSettingsType } from './saved_objects';
 import { registerRoutes } from './routes';
 import { getCoreSettings } from './settings';
+import { UiSettingsDefaultsClient } from './ui_settings_defaults_client';
 
 export interface SetupDeps {
   http: InternalHttpServiceSetup;
@@ -56,16 +57,12 @@ export class UiSettingsService
 
     this.register(getCoreSettings({ isDist: this.isDist }));
 
-    const { version, buildNum } = this.coreContext.env.packageInfo;
     return {
       createDefaultsClient: () =>
-        new UiSettingsClient({
-          type: 'config',
-          id: version,
-          buildNum,
+        new UiSettingsDefaultsClient({
           defaults: mapToObject(this.uiSettingsDefaults),
           overrides: this.overrides,
-          log: this.log,
+          log: this.log.get('core defaults'),
         }),
     };
   }