.env.sample 🆕 Best

API_KEY=
DB_HOST=
DB_USER=
DB_PASS=
MODE=

.env.sample          # common vars
.env.sample.dev      # dev overrides
.env.sample.prod     # prod overrides (still no real secrets)

SESSION_TIMEOUT=86400

A bad sample file is just a list of KEY=. A great sample file is a work of documentation. Here is the anatomy of a professional .env.sample: .env.sample