Bool returns the boolean value of the named environment variable.

BoolDefaultTrue is like Bool, but returns true by default if the environment variable isn't present.

CanSSHD is whether the Tailscale SSH server is allowed to run.

LogCurrent logs the currently set environment knobs.

LookupBool returns the boolean value of the named environment value.

LookupInt returns the integer value of the named environment value.

OptBool is like Bool, but returns an opt.Bool, so the caller can distinguish between implicitly and explicitly false.

SSHIgnoreTailnetPolicy is whether to ignore the Tailnet SSH policy for development.

SSHPolicyFile returns the path, if any, to the SSHPolicy JSON file for development.

String returns the named environment variable, using os.Getenv.

UseWIPCode is whether TAILSCALE_USE_WIP_CODE is set to permit use of Work-In-Progress code.