You can either use the name or identifier of a parameter in the configuration file.
For example, if you want to double a foe's default max hp by 2 and additive hp by 3, you can do it via identifiers like this:
{0, 2.00, 3.00}
or via names like this:
{stats.maxHp, 2.00, 3.00}
or this:
{stats["maxHp"], 2.00, 3.00}
All names are case insensitive, so you can even use stats.MaXhP if you want.
Names give a better overview of the configuration file while identifiers keep it shorter and a bit more neatly formatted. You can choose whichever style you prefer more.
Notes
For a list of all names, you can view the {game}/x64/scripts/config/TheInsurgentsScalableFoes/helpers.lua file.