- Removing bulk of the noise from inline documentation.
- Packages bundled into single line like previous the Alpine version had.
- `CACHE_ZYPPER` is only used as an `ARG` in the `builder` stage.
- `zypper clean` wasn't able to clear anything from the install root, other than the `CACHE_ZYPPER` mount.
The additions from `adduser` reading `/etc` does not appear to apply if the directory already exists, and permissions (including SGID) are adjusted properly for the home dir.
This mean the excess backup copies in `/etc` are introduced again however.
BusyBox `adduser` was reading config from `/etc` that unnecessarily populates the home folder with various dot files.
Alternative approach is to create the user and home folder manually. This avoids some extra files like the `-` suffixed backup copies from `adduser`.
- If local folder ownership is for example `644` it will fail to handle the `COPY` regardless (while `744` would work).
- Creating the directory with higher permissions in the container does not appear to help.
Create `testssl` user (_and group_) with no password (`-D`) and default their shell to bash (`-s`):
- A group will implicitly be created with the same value as the user. `addgroup testssl` and `-G testssl` are not needed.
- Gecos data (`-g "testssl user"`) doesn't appear relevant to the project to be required? The default gecos value (`Linux User,,,`) should be fine.