Juraj:
one .ino must have the same name as the project folder. it should contain global variables because it is first in the final concatenation of ino files. the rest is concatenated in alphabet order
OK the first tab with the same name as the project folder contains nothing to compile: only comments.
The rest is in alphabetic order, a_libraries and declarations contains the global variables.
Nevertheless it does not work. The compiler gets weird: it brings me an
exit status 1
expected ';' before ')' token
for a line of code that is in a large commented out block! :-/
P.S. I found the error elsewhere, but with tabbed code the compiler brings the wrong line numbers in its error reporting.
This appears to be a bug.