{#- prologue -#}
{%- set preserve_env = ( j2cfg.core_preserve_environment or [] )|env_any_to_str_list -%}
{%- set preserve_vars = preserve_env|str_list_re_fullmatch('[^=]+') -%}
{#- main part -#}
{% for v in preserve_vars -%}
{{ v }}
{% endfor -%}