Crossbar container image is too large

[ivanov17]

Hello. I see that the crossbar container image is too large for both versions:

$ podman images
REPOSITORY                     TAG              IMAGE ID      CREATED       SIZE
docker.io/crossbario/crossbar  pypy-slim-amd64  368bcef639c4  5 months ago  2.12 GB
docker.io/crossbario/crossbar  cpy-slim-amd64   3c87de7c5ca0  5 months ago  2.12 GB

The largest is the /root directory:

root@0426f94b2365:~# du -xsh /* | sort -h
0	/=1.15.10
0	/boot
0	/dev
0	/home
0	/lib64
0	/media
0	/mnt
0	/opt
0	/proc
0	/run
0	/srv
0	/sys
12K	/node
1000K	/etc
3.0M	/tmp
4.4M	/sbin
5.7M	/bin
9.8M	/lib
12M	/var
810M	/usr
1.3G	/root

There are several dot files in the /root directory:

root@0426f94b2365:~# ls -la /root
total 12
drwx------. 1 root root  20 Feb  8 02:45 .
dr-xr-xr-x. 1 root root  28 Aug  3 14:13 ..
-rw-r--r--. 1 root root 592 Feb  8 02:45 .bashrc
drwxr-xr-x. 1 root root  17 Feb  8 02:45 .cache
drwxr-xr-x. 3 root root  28 Feb  8 02:45 .cargo
-rw-r--r--. 1 root root 182 Feb  8 02:45 .profile
drwxr-xr-x. 6 root root  94 Feb  8 02:46 .rustup
-rw-r--r--. 1 root root 254 Feb  4 11:26 .wget-hsts

And the largest one is the .rustup subdirectory:

root@0426f94b2365:~# du -xsh /root/.rustup
1.2G	/root/.rustup

Also I see the directory named =1.15.10 at the root of the container, and it makes me thing that something went wrong while building the image.

Are rust binaries really needed for the crossbar process to work?