Targets are used in Avalon macros and aliases to refer to portions of your macro/alias likely to change rapidly and need to be altered quickly, without having to redo whole macros or aliases.
You have ten targets available. They can be set or changed using the ST <target> <content> or to change the first target simply TT <content>.
You refer to targets in macros and aliases using ! followed by the target number, with no space between the ! and the number, e..g. !2 means target #2.