Checks based on environment variables at runtime, so you don’t get situations where it’s half censored, half not. must have one or two attributes. If two, one attribute must be “not” which negates the condition. If the other attribute starts with ! that also negates the condition. Possibly twice. Once any ! has been stripped off, the condition is “the environment variable by that name exists.”

You can do call the general that only evaluates as true if the environment variable “something” is set to “silly” The string is URL decoded before comparing with the environment. Don’t do ... because XML sucks and you should just specify an attribute w/out an equals sign when you want it to merely exist.