The Debug -> Macros tab is displayed only when macro debugging is enabled. This can be achieved either by configuring certain settings in Site Manager -> Settings -> System -> Debug, or by adding specific keys to the appSettings section of your project's web.config file. Both options are described in this context help topic.
On this tab, you can see which macros were recently resolved. For each macro, the log displays the exact expression, the result (the value into which it was resolved) and the context from which it was called. If detailed macro debugging is enabled, the results will also be displayed for individual sub‑elements that make up each macro expression. This is useful if you want to analyze how macros were processed.
Enabling the Show complete context checkbox displays complete context (not only the topmost item) in the Context column. The log can be cleared using the Clear macro log button.
For more information about debugging in Kentico CMS, please refer to Developer's Guide -> Development -> Debugging and system information.