Trying to understand files and folders in data folder

in the following folder:
/opt/mailcow-dockerized/mailcow-dockerized/data/conf/postfix/

In the main.cf I have the following entries:

smtpd_tls_cert_file = /etc/ssl/mail/cert.pem
smtpd_tls_key_file = /etc/ssl/mail/key.pem
tls_server_sni_maps = hash:/opt/postfix/conf/sni.map

There is no /etc/ssl/mail folder on my system
There is no /opt/postfix/ folder on my system.

My mailcow is running just fine.

How does this work?
Thanks

accolon
First I don’t have a .data folder . Mine is just called data.

I would like to note that mailcow is installed on a arch linux machine.
It is working just fine and I installed it per the instructions.

Here is the tree of my /opt folders:

[demo@mail opt]$ ls -la
total 20
drwxr-xr-x  5 root root 4096 May 13 09:13 .
drwxr-xr-x 18 root root 4096 Apr 21 03:13 ..
drwx--x--x  4 root root 4096 May  7 10:56 containerd
drwxr-xr-x  3 root root 4096 May  7 10:49 mailcow-dockerized
drwxr-xr-x  5 root root 4096 May 13 09:13 sublime_text

[demo@mail mailcow-dockerized]$ ls -la
total 12
drwxr-xr-x 3 root root 4096 May  7 10:49 .
drwxr-xr-x 5 root root 4096 May 13 09:13 ..
drwxr-xr-x 7 root root 4096 May 31 10:02 mailcow-dockerized

[demo@mail mailcow-dockerized]$ cd mailcow-dockerized/
[demo@mail mailcow-dockerized]$ ls -la
total 196
drwxr-xr-x 7 root root  4096 May 31 10:02 .
drwxr-xr-x 3 root root  4096 May  7 10:49 ..
-rw-r--r-- 1 root root  3223 May  7 10:49 CODE_OF_CONDUCT.md
-rw-r--r-- 1 root root  1003 May  7 10:49 CONTRIBUTING.md
-rwxr-xr-x 1 root root   174 May  7 10:49 create_cold_standby.sh
drwxr-xr-x 7 root root  4096 May  7 10:49 data
-rw-r--r-- 1 root root 22564 May 31 10:01 docker-compose.yml
-rw-r--r-- 1 root root   414 May  7 10:49 .editorconfig
lrwxrwxrwx 1 root root    12 May  7 10:49 .env -> mailcow.conf
-rwxr-xr-x 1 root root 18578 May  7 10:49 generate_config.sh
drwxr-xr-x 8 root root  4096 May 31 10:01 .git
drwxr-xr-x 4 root root  4096 May  7 10:49 .github
-rw-r--r-- 1 root root  1774 May  7 10:49 .gitignore
drwxr-xr-x 3 root root  4096 May 31 10:01 helper-scripts
-rw-r--r-- 1 root root 35141 May  7 10:49 LICENSE
-rw------- 1 root root  8467 May 31 10:02 mailcow.conf
-rwxr-xr-x 1 root root   126 May 22 09:40 netfilter.sh
-rw-r--r-- 1 root root  1908 May  7 10:49 README.md
-rw-r--r-- 1 root root  1737 May  7 10:49 SECURITY.md
drwxr-xr-x 2 root root  4096 May 31 09:59 update_diffs
-rwxr-xr-x 1 root root 44366 May 26 14:18 update.sh

[demo@mail mailcow-dockerized]$ cd data
[demo@mail data]$ ls -la
total 28
drwxr-xr-x  7 root root 4096 May  7 10:49 .
drwxr-xr-x  7 root root 4096 May 31 10:02 ..
drwxr-xr-x  8 root root 4096 May  7 10:53 assets
drwxr-xr-x 11 root root 4096 May  7 10:49 conf
drwxr-xr-x 16 root root 4096 May  7 10:49 Dockerfiles
drwxr-xr-x  8 root root 4096 May  7 10:49 hooks
drwxr-xr-x 12 root root 4096 May  7 11:00 web

[demo@mail data]$ cd assets
[demo@mail assets]$ ls -la
total 32
drwxr-xr-x 8 root root 4096 May  7 10:53 .
drwxr-xr-x 7 root root 4096 May  7 10:49 ..
drwxr-xr-x 2 root root 4096 May  7 10:49 mysql
drwxr-xr-x 2 root root 4096 May  7 10:49 nextcloud
drwxr-xr-x 2 root root 4096 May  7 10:49 passwd
drwxr-xr-x 4 root root 4096 Jun 16 12:14 ssl
drwxr-xr-x 2 root root 4096 May  7 10:49 ssl-example
drwxr-xr-x 2 root root 4096 May  7 10:49 templates

[demo@mail assets]$ cd ssl
[demo@mail ssl]$ ls -la
total 32
drwxr-xr-x 4 root root 4096 Jun 16 12:14 .
drwxr-xr-x 8 root root 4096 May  7 10:53 ..
drwxr-xr-x 2 root root 4096 May  7 11:04 acme
-rw-r--r-- 1 root root 5946 Jun 16 12:14 cert.pem
-rw-r--r-- 1 root root  424 May  7 10:53 dhparams.pem
-rw------- 1 root root 3272 Jun 16 12:14 key.pem
drwxr-xr-x 2 root root 4096 May  7 11:05 mail.dccathome.com

mlcwuser whatever from the directory listings above I don’t have etc dir anywhere under the /opt folders. Not that I can find anyway.

mlcwuser So maybe I need to ask the question. How do I see the path in the container?
Is that the correct question? Because I don’t see etc/ssl/mail

I am going to do some more research. That command line was what I was looking for. That helps
My /opt does not get me to the same place. I get 2 different folder lists when I do a ls or ls -la in each of those places.
Thanks for your help . I will take it from here.