Mark runtime-only fields of serialisable types [NonSerialized] The Unity 6.7 and CoreCLR branch had to mark these public fields [NonSerialized] for Unity 6.7's serialisation: entity references, runtime collections, Item and ItemContainer instances, TimeSince and the like. None of their types is [Serializable] or a type Unity serialises natively on main, so Unity 6.3 already skips them and nothing changes on Mono; the attribute only says so explicitly, and main won't need it added again when it moves to 6.7. Cherry-picked unchanged from unity_6.7.0's changeset 169804 (7044676f3ae, "Add more serialisation attributes for Unity 6.7"). (cherry picked from commit 7044676f3ae5ec8f854e83a2e0fb42d1b28cbf64) Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>