Interface XenvConfigSpecOption

default value, or a function that returns the default value

env var name(s) to read the value from.

• true: use the config key itself as the env var name
• string: use this exact env var name
• string[]: use the first env var name in the list that exists

map raw env var string values to other values before further processing

transform the resolved value (and its trace) before it's placed in the result

value type used to coerce a found value