> In theory, you could also use perl -V:uname to derive just that string. But it didn't work for me though the other variables from perl -V do.

https://metacpan.org/dist/perl/source/Porting/Glossary#L5553:

uname: This variable is used internally by Configure to determine the full pathname (if any) of the uname program. After Configure runs, the value is reset to a plain "uname" and is not useful.

https://metacpan.org/dist/perl/source/Porting/Glossary#L4456:

myuname: The output of 'uname -a' if available, otherwise the hostname. The whole thing is then lower-cased and slashes and single quotes are removed.

There are a few of the other %Config / -V: entries that have the "my" versions, as listed in the glossary near myuname . And you can find others that have "is not useful" in their description, indicating that the $Config{xxx} or -V:xxx will not be useful. (edit: Though their "is not useful" assessment doesn't always match my experience: on Strawberry perl, 'make' stays with either dmake (for older versions) or gmake (for more recent strawberries), and is useful.)