7 files declare their use of AttributeBag in Zircon Profile 8

AttributeBagTest.php in vendor/symfony/http-foundation/Tests/Session/Attribute/AttributeBagTest.php

MockArraySessionStorageTest.php in vendor/symfony/http-foundation/Tests/Session/Storage/MockArraySessionStorageTest.php

MockFileSessionStorageTest.php in vendor/symfony/http-foundation/Tests/Session/Storage/MockFileSessionStorageTest.php

NativeSessionStorageTest.php in vendor/symfony/http-foundation/Tests/Session/Storage/NativeSessionStorageTest.php

PhpBridgeSessionStorageTest.php in vendor/symfony/http-foundation/Tests/Session/Storage/PhpBridgeSessionStorageTest.php

Session.php in vendor/symfony/http-foundation/Session/Session.php

SessionTest.php in vendor/symfony/http-foundation/Tests/Session/SessionTest.php