I made a small (< 7 Mb) footage of me expanding a macro through Geiser
The macro I am expanding is defined in the Guix code and it is supposed to deliver some forms creating and manipulating srfi-9 forms (records)
but the result I see is a piece of code creating and manipulating a structure
It seems to me that also the vanilla srfi-9 forms have been expanded and I' m getting the lowest level possible (there are no more macros to expand in the code I am seeing)
In the Guile NEWS file I read this excerpt
** `macroexpand' produces structures, not S-expressions.
Given the need to maintain referential transparency, both lexically and
modular, the result of expanding Scheme expressions is no longer itself
an s-_expression_. If you want a human-readable approximation of the
result of `macroexpand', call `tree-il->scheme' from `(language
tree-il)'.