If you use "-d" you'll get the info you want:
No implicit rule found for 'default'.
Considering target file 'lib'.
Finished prerequisites of target file 'lib'.
No need to remake target 'lib'; using VPATH name 'apps/lib'.
Finished prerequisites of target file 'default'.
Only adding 'MAKEFLAGS += --warn-undefined-variables' is somewhat
helpful.
You should feel free to do that, if your makefiles are written such
that it doesn't give spurious warnings. Make has silently expanded
empty variables to the empty string for 40 years and changing that as
the default behavior is not an option.