v7.02 · Added Execute Macro to Keyboard Maestro action list category

Perhaps it's the categorisation that is new rather than the execute macro action ?

If you look at the macros which resize and position windows in this library:

you will see that each of the keyboard assigned macros executes one or more shared 'library' macros to calculate a value (e.g. the index of the next grid position) or carry out an action (size and position the window)