6 files declare their use of SessionBagInterface in Zircon Profile 8.0

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

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

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

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

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

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