What problem does this solve or what need does it fill?

There are a set of uses cases where a user may want to mutably access some type that implements change detection (e.g. Mut) without actually triggering change detection.

What solution would you like?

An API exposed for these type e.g. get_untracked() or something like that which returns a &mut T to the inner type but does not cause is_changed() to return true.

What alternative(s) have you considered?

Using unsafe primitives UnsafeCell, or wrapping them in something like a Mutex to get mutable access immutably. However, these are quite a bit overkill and add unnecessary unsafe and overhead.