Configuration files have a /well defined/ layout? I don't have to guess if it is YES|NO|TRUE|FALSE|0|1... or does it use quotes or no quotes around the variable

Configuration files have a /well defined/ layout? I don't have to guess if it is YES|NO|TRUE|FALSE|0|1... or does it use quotes or no quotes around the variable and/or value? Or a space between the variable and the equals sign? Hard to tell with a config file.