This might be a stupid question, but I wasn't able to find any relations in any docs. When using traefik as revers-proxy for Docker container, I have seen many configuration examples and at some of them there is a command/syntax I don't really understand.
For example, in the labels section of a docker-compose.yml file is a label like:
- com.example.key=value@file
What does this @file do or mean? Is this specific for docker-compose or for traefik?
That says which provider to use to read Traefik configuration, see example here: https://www.smarthomebeginner.com/traefik-2-docker-tutorial/