Scale/Sandbox/Docker - localtime:ro

Hi All, just setup sandbox and docker on my home NAS. Following Stux youtube guide, ive got majority of my apps moved from TrueCharts/ TrueNAS to my jlmkr instance via Dockge.
Im a newbie with most of this, some of my docker-compose request the following volume - /etc/localtime:/etc/localtime:ro
Im trying to understand what this is and how i bind it in my docker .yaml file.
i assume its to pass the local time of the host to docker, ive been setting the TZ=Australia/Brisbane in my compose, is this not the same thing.
Ive tried deleting - /etc/localtime:/etc/localtime:ro from the yaml but the apps dont load so i assume its required.
Any assistance or direction on this would be much appreciated.

Dragonfish-24.04.2
i7-7700 - 32GB RAM - 1TB Apps SSD - 1 x RAIDZ2 | 8 wide | 7.28 TiB

This might help

localtime.

The /etc/localtime file configures the system-wide timezone of the local system that is used by applications for presentation to the user. It should be an absolute or relative symbolic link pointing to /usr/share/zoneinfo/, followed by a timezone identifier such as “Europe/Berlin” or “Etc/UTC”. The resulting link should lead to the corresponding binary tzfile(5) timezone data for the configured timezone.

Which means if you map a time zone file to /etc/localtime in the socket it should work.

It’s basically a different way to specify the time zone into the container.

Alternatively, you could make the symbolic link in your jail, then the volume bind would work.

ln -s makes symbolic links