Why does deriving AnyBitPattern automatically derive Zeroable but Pod does not?

[asasine]

Adding derive(AnyBitPattern) to a type will automatically add an unsafe impl Zeroable for MyType {} but the same doesn't happen when you derive(Pod), despite both having a Zeroable supertrait. Why do these two derives behave differently? You always have to derive(Pod, Zeroable), but you can't derive(AnyBitPattern, Zeroable) as that creates a conflicting implementation of Zeroable.

---

Example

use bytemuck::{AnyBitPattern, Pod, Zeroable};

#[derive(Pod, Copy, Clone)]
#[repr(C)]
struct MyPod;

#[derive(Zeroable, Copy, Clone)]
#[repr(C)]
struct MyPodZeroable;

#[derive(AnyBitPattern, Copy, Clone)]
struct MyAnyBitPattern;

#[derive(AnyBitPattern, Zeroable, Copy, Clone)]
struct MyAnyBitPatternZeroable;

When compiled, these errors are produced.

error[E0277]: the trait bound `MyPod: Zeroable` is not satisfied
  --> src\lib.rs:5:8
   |
 5 | struct MyPod;
   |        ^^^^^ the trait `Zeroable` is not implemented for `MyPod`
   |
   = help: the following other types implement trait `Zeroable`:
             ()
             (A, B)
             (A, B, C)
             (A, B, C, D)
             (A, B, C, D, E)
             (A, B, C, D, E, F)
             (A, B, C, D, E, F, G)
             (A, B, C, D, E, F, G, H)
           and 82 others
note: required by a bound in `Pod`
  --> D:\usr\share\cargo\registry\src\index.crates.io-1949cf8c6b5b557f\bytemuck-1.24.0\src\pod.rs:37:23
   |
37 | pub unsafe trait Pod: Zeroable + Copy + 'static {}
   |                       ^^^^^^^^ required by this bound in `Pod`

error[E0119]: conflicting implementations of trait `Zeroable` for type `MyAnyBitPatternZeroable`
  --> src\lib.rs:14:25
   |
14 | #[derive(AnyBitPattern, Zeroable, Copy, Clone)]
   |          -------------  ^^^^^^^^ conflicting implementation for `MyAnyBitPatternZeroable`
   |          |
   |          first implementation here
   |
   = note: this error originates in the derive macro `Zeroable` (in Nightly builds, run with -Z macro-backtrace for more info)

Some errors have detailed explanations: E0119, E0277.
For more information about an error, try `rustc --explain E0119`.

[Lokathor]

Probably it got this way on accident.

I think a change now would break someone somewhere, and it's only a minor annoying thing really, so it's just that way until at least 2.0.