Hm, I was using a file viewer, not strings to examine the file and I looked for the text "GCC". That must be the difference. Indeed, strings does not show that string nor any string containing "GCC"
Here is a small part of the text in the file (compiled without -O2, as with it some characters appear mangled): GCC version 10.2.0-mtune=generic -march=x86-64staticv.f90 D ΓΏ Trace/breakpoint trap SIGTRAP Terminal quit signal Regards, Arjen