Allow persistant modifiable env vars, as long as n8n container is running.
Sometimes you have only a small dataset (simple flags) that you must store persistant, for this cases a db or redis or anything else external is to much.
Allow with env var:
N8N_PERSISTANT_ENV = true
Restrict to a workspace number:
N8N_PERSISTANT_ENV_4711 = true
Within your nodes you can store and access the ENV_{name} (not all env, only prefixd with ENV_ or $env.).
Optionally this vars are stored in data-folder and are available on restart.