These environment variables will change the behavior of the app:

• DEVTOOLS=1 — start with Chromium Devtools open — useful when something goes wrong before the F12 binding becomes available.
• ITCH_LOG_LEVEL=debug — see logger/index for available levels - defaults to "info"
• DEBUG=butlerd:* — show all debug messages related to communicating with the butler daemon.
• MARCO_POLO=1 — dumps all redux events being dispatched throughout the app. We attempt to filter that but please pay extra care to any logs you post publicly to make sure you're not leaking your own credentials.
• IMMEDIATE_NOSE_DIVE=1 - open dev tools before launching html games
• UP_TO_SCRATCH=1 - force update checks, even in development environment
• PROFILE_REQUIRE=1 - profile how much time it takes to require modules
• ITCH_IGNORE_CERTIFICATE_ERRORS=1 - ignore certificate errors - USE WITH CARE only with debugging proxies that do SSL proxying
• ITCH_EMULATE_OFFLINE=1 - simulate a network outage. This only affects itch, not butler.

See the Performance hacking section for other environment variables that impact the app.