Same image has different list files of 'docker save' by tag and digest

[myback]

Description

Same image saved by tag and digest has a different list of files inside the archive. The archive saved by digest has not "repositories" file. Any image saved in both variants has a different list of files inside the archive.

Reproduce

~ docker pull alpine:3.17
...
Digest: sha256:124c7d2707904eea7431fffe91522a01e5a861a624ee31d03372cc1d138a3126
...
~ docker save alpine:3.17 -o alpine_tag.tar
~ docker save alpine@sha256:124c7d2707904eea7431fffe91522a01e5a861a624ee31d03372cc1d138a3126 -o alpine_digest.tar

~ tar tvf alpine_tag.tar
...
-rw-r--r-- 0/0            1470 2023-03-29 18:19 9ed4aefc74f6792b5a804d1d146fe4b4a2299147b0f50eaf2b08435d7b38c27e.json
-rw-r--r-- 0/0             202 1970-01-01 00:00 manifest.json
-rw-r--r-- 0/0              89 1970-01-01 00:00 repositories

~ tar tvf alpine_digest.tar
...
-rw-r--r-- 0/0            1470 2023-03-29 18:19 9ed4aefc74f6792b5a804d1d146fe4b4a2299147b0f50eaf2b08435d7b38c27e.json
-rw-r--r-- 0/0             202 1970-01-01 00:00 manifest.json

Expected behavior

No response

docker version

Client: Docker Engine - Community
 Version:           23.0.2
 API version:       1.42
 Go version:        go1.19.7
 Git commit:        569dd73
 Built:             Mon Mar 27 16:16:18 2023
 OS/Arch:           linux/amd64
 Context:           default

Server: Docker Engine - Community
 Engine:
  Version:          23.0.2
  API version:      1.42 (minimum version 1.12)
  Go version:       go1.19.7
  Git commit:       219f21b
  Built:            Mon Mar 27 16:16:18 2023
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v1.6.2
  GitCommit:        de8046a5501db9e0e478e1c10cbcfb21af4c6b2d
 runc:
  Version:          1.1.5
  GitCommit:        v1.1.5-0-gf19387a
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

Client:
 Context:    default
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.10.4
    Path:     /usr/libexec/docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.17.2
    Path:     /usr/libexec/docker/cli-plugins/docker-compose
  scan: Docker Scan (Docker Inc.)
    Version:  v0.23.0
    Path:     /usr/libexec/docker/cli-plugins/docker-scan

Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 3
 Server Version: 23.0.2
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: systemd
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: de8046a5501db9e0e478e1c10cbcfb21af4c6b2d
 runc version: v1.1.5-0-gf19387a
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 5.15.0-69-generic
 Operating System: Ubuntu 20.04.6 LTS
 OSType: linux
 Architecture: x86_64
 CPUs: 8
 Total Memory: 15.54GiB
 Name: mini.sh0.dev
 ID: 53811690-5670-4eae-9208-716ca6107a38
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

Additional Info

This issue is reproducible on Linux and docker-desktop on MacOS

[myback]

Or maybe it's a feature. This file is used for backwards compatibility only.