C:\>perl -le "print 'PERL5OPT: ' . $ENV{PERL5OPT}; print for @INC;"
PERL5OPT:
C:/perl-5.34.0/site/lib/MSWin32-x64-multi-thread
C:/perl-5.34.0/site/lib
C:/perl-5.34.0/lib/MSWin32-x64-multi-thread
C:/perl-5.34.0/lib

C:\>set PERL5OPT=-MMy_INC

C:\>perl -le "print 'PERL5OPT: ' . $ENV{PERL5OPT}; print for @INC;"
PERL5OPT: -MMy_INC
/ajperznes/perl/localperl
/ajperznes/perl/lib/5.32.0/x86_64-linux
/ajperznes/perl/lib/5.32.0
/ajperznes/perl/lib/site_perl/5.32.0/x86_64-linux
/ajperznes/perl/lib/site_perl/5.32.0
/ajperznes/perl/lib/5.32.0/x86_64-linux
/ajperznes/perl/lib/5.32.0

C:\>