Many fields and functions in Match-IT require special values that have specific meanings. There are mnemonics for most of these that you can use in Lua. This means you can refer to these special constant values by a mnemonic name rather than having to know the specific value. The constants available are all defined in the reference section. They can be accessed for reading (only) as m.ConstantName, where ConstantName is the name as you see it in the help system. They are returned as native Lua numbers or strings.