cpan> install Par::Packer
Warning: Cannot install Par::Packer, don't know what it is.
Try the command

    i /Par::Packer/

to find objects with matching identifiers.

cpan> i /Par::Packer/
Fetching with LWP:
http://cpan.strawberryperl.com/authors/id/R/RS/RSCHUPP/CHECKSUMS
Module id = PAR::Packer
    CPAN_USERID  RSCHUPP (Roderich Schupp <rschupp@cpan.org>)
    CPAN_VERSION 1.049
    CPAN_FILE    R/RS/RSCHUPP/PAR-Packer-1.049.tar.gz
    UPLOAD_DATE  2019-05-31
    INST_FILE    (not installed)