arm32v7/buildpack-deps:bionic-* images don't seem correct

I am confused at why the base layers of the arm32v7/buildpack-deps:bionic-* images are different than the arm32v7/ubuntu:bionic images.

docker history --no-trunc arm32v7/buildpack-deps:bionic-curl
IMAGE                                                                     CREATED             CREATED BY                                                                                                                                                                             SIZE                COMMENT
sha256:20754fee7abf041e9fd7fbbe677447d84ec5bdc015c6ea8e0c883a1c9e34997f   44 hours ago        /bin/sh -c set -ex;  if ! command -v gpg > /dev/null; then   apt-get update;   apt-get install -y --no-install-recommends    gnupg    dirmngr   ;   rm -rf /var/lib/apt/lists/*;  fi   0B
<missing>                                                                 44 hours ago        /bin/sh -c apt-get update && apt-get install -y --no-install-recommends   ca-certificates   curl   wget  && rm -rf /var/lib/apt/lists/*                                                13MB
<missing>                                                                 2 weeks ago         /bin/sh -c #(nop)  CMD ["bash"]                                                                                                                                                        0B
<missing>                                                                 2 weeks ago         /bin/sh -c #(nop) ADD file:1fdf1946f816fc31d9b70835fe5cc0346daccdfa3c06a8420b30437b9df12c84 in /                                                                                       80.6MB

 docker history --no-trunc arm32v7/ubuntu:bionic
IMAGE                                                                     CREATED             CREATED BY                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 SIZE                COMMENT
sha256:b47afe3525fa5431d9adb152197e2c0156303b7c7d6f5a4769b41ef29dbb05ac   3 weeks ago         /bin/sh -c #(nop)  CMD ["/bin/bash"]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       0B
<missing>                                                                 3 weeks ago         /bin/sh -c mkdir -p /run/systemd && echo 'docker' > /run/systemd/container                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 7B
<missing>                                                                 3 weeks ago         /bin/sh -c sed -i 's/^#\s*\(deb.*universe\)$/\1/g' /etc/apt/sources.list                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   2.83kB
<missing>                                                                 3 weeks ago         /bin/sh -c rm -rf /var/lib/apt/lists/*                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     0B
<missing>                                                                 3 weeks ago         /bin/sh -c set -xe   && echo '#!/bin/sh' > /usr/sbin/policy-rc.d  && echo 'exit 101' >> /usr/sbin/policy-rc.d  && chmod +x /usr/sbin/policy-rc.d   && dpkg-divert --local --rename --add /sbin/initctl  && cp -a /usr/sbin/policy-rc.d /sbin/initctl  && sed -i 's/^exit.*/exit 0/' /sbin/initctl   && echo 'force-unsafe-io' > /etc/dpkg/dpkg.cfg.d/docker-apt-speedup   && echo 'DPkg::Post-Invoke { "rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true"; };' > /etc/apt/apt.conf.d/docker-clean  && echo 'APT::Update::Post-Invoke { "rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true"; };' >> /etc/apt/apt.conf.d/docker-clean  && echo 'Dir::Cache::pkgcache ""; Dir::Cache::srcpkgcache "";' >> /etc/apt/apt.conf.d/docker-clean   && echo 'Acquire::Languages "none";' > /etc/apt/apt.conf.d/docker-no-languages   && echo 'Acquire::GzipIndexes "true"; Acquire::CompressionTypes::Order:: "gz";' > /etc/apt/apt.conf.d/docker-gzip-indexes   && echo 'Apt::AutoRemove::SuggestsImportant "false";' > /etc/apt/apt.conf.d/docker-autoremove-suggests   745B
<missing>                                                                 3 weeks ago         /bin/sh -c #(nop) ADD file:886ddcd1b8d1c90b4eb406530752924e28c90f8252af281e708532d67def3c2c in /                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           68MB

I am running into things that appear to be missing from the buildpack-deps image for example apt is missing, the registered package feeds are different therefore packages available on arm32v7/ubuntu:bionic are unavailable "out of the box" on arm32v7/buildpack-deps:bionic-*

 docker run -it --rm  arm32v7/buildpack-deps:bionic-scm grep -h ^deb /etc/apt/sources.list /etc/apt/sources.list.d/*
deb http://deb.debian.org/debian wheezy main
deb http://deb.debian.org/debian wheezy-updates main
deb http://security.debian.org wheezy/updates main

docker run -it --rm  arm32v7/ubuntu:bionic grep -h ^deb /etc/apt/sources.list /etc/apt/sources.list.d/*
deb http://ports.ubuntu.com/ubuntu-ports/ bionic main restricted
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-updates main restricted
deb http://ports.ubuntu.com/ubuntu-ports/ bionic universe
deb-src http://ports.ubuntu.com/ubuntu-ports/ bionic universe
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-updates universe
deb-src http://ports.ubuntu.com/ubuntu-ports/ bionic-updates universe
deb http://ports.ubuntu.com/ubuntu-ports/ bionic multiverse
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-updates multiverse
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-backports main restricted universe multiverse
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-security main restricted
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-security universe
deb-src http://ports.ubuntu.com/ubuntu-ports/ bionic-security universe
deb http://ports.ubuntu.com/ubuntu-ports/ bionic-security multiverse

Docker version

Client:
 Version:       18.02.0-ce
 API version:   1.29 (downgraded from 1.36)
 Go version:    go1.9.3
 Git commit:    fc4de44
 Built: Wed Feb  7 21:16:33 2018
 OS/Arch:       linux/amd64
 Experimental:  false
 Orchestrator:  swarm

Server:
 Engine:
  Version:      17.05.0-ce
  API version:  1.29 (minimum version 1.12)
  Go version:   go1.7.5
  Git commit:   89658be
  Built:        Thu May  4 22:30:54 2017
  OS/Arch:      linux/arm
  Experimental: false

Docker info

Containers: 9
 Running: 0
 Paused: 0
 Stopped: 9
Images: 60
Server Version: 17.05.0-ce
Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host macvlan null overlay
 Log:
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 9048e5e50717ea4497b757314bad98ea3763c145
runc version: 9c2d8d184e5da67c95d601382adf14862e4f2228
init version: 949e6fa
Kernel Version: 4.9.35-v7+
Operating System: Raspbian GNU/Linux 8 (jessie)
OSType: linux
Architecture: armv7l
CPUs: 4
Total Memory: 923.4MiB
Name: raspberrypi
ID: 3UO3:FS2Q:BZB2:GFD5:5AVY:R4FH:OCFJ:IQ4C:7MCH:TGAH:RCFG:CAWQ
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false

WARNING: No swap limit support
WARNING: No cpu cfs quota support
WARNING: No cpu cfs period support
WARNING: No cpuset support

docker-library / buildpack-deps

arm32v7/buildpack-deps:bionic-* images don't seem correct #75

Docker version

Docker info