Remove methods, point to interface.

app/Support/Repositories/UserGroup/UserGroupInterface.php

@@ -0,0 +1,45 @@
+<?php
+
+/*
+ * UserGroupInterface.php
+ * Copyright (c) 2025 james@firefly-iii.org.
+ *
+ * This file is part of Firefly III (https://github.com/firefly-iii).
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see https://www.gnu.org/licenses/.
+ */
+
+declare(strict_types=1);
+
+namespace FireflyIII\Support\Repositories\UserGroup;
+
+use FireflyIII\Enums\UserRoleEnum;
+use FireflyIII\Models\UserGroup;
+use FireflyIII\User;
+use Illuminate\Contracts\Auth\Authenticatable;
+
+interface UserGroupInterface
+{
+    public function getUserGroup(): ?UserGroup;
+
+    public function getUser(): ?User;
+
+    public function checkUserGroupAccess(UserRoleEnum $role): bool;
+
+    public function setUserGroup(UserGroup $userGroup): void;
+
+    public function setUser(null|Authenticatable|User $user): void;
+
+    public function setUserGroupById(int $userGroupId): void;
+}

app/Support/Repositories/UserGroup/UserGroupTrait.php

@@ -40,11 +40,16 @@ trait UserGroupTrait
     protected ?User      $user      = null;
     protected ?UserGroup $userGroup = null;
 
-    public function getUserGroup(): UserGroup
+    public function getUserGroup(): ?UserGroup
     {
         return $this->userGroup;
     }
 
+    public function getUser(): ?User
+    {
+        return $this->user;
+    }
+
     public function checkUserGroupAccess(UserRoleEnum $role): bool
     {
         $result = $this->user->hasRoleInGroupOrOwner($this->userGroup, $role);