podman/docs/source/markdown/options/env.image.md

####> This option file is used in: ####> podman build, farm build ####> If file is edited, make sure the changes ####> are applicable to all of those.

--env=env[=value]

Add a value (e.g. env=value) to the built image. Can be used multiple times. If neither = nor a value are specified, but env is set in the current environment, the value from the current environment is added to the image. To remove an environment variable from the built image, use the --unsetenv option.