debootstrap is unable to operate if the packages being included have a
virtual dependency which is not otherwise resolved.

Easy reproducer:
  # debootstrap --include=libnet-ssleay-perl stretch stretch
  [...]
  W: Failure while configuring base packages.  This will be re-attempted up to five times.
  W: See debootstrap.log for details (possibly the package libnet-ssleay-perl is at fault)

The log shows error:
  dpkg: dependency problems prevent configuration of libnet-ssleay-perl:
   libnet-ssleay-perl depends on perl-openssl-abi-1.1; however:
    Package perl-openssl-abi-1.1 is not installed.

libnet-ssleay-perl depends on perl-openssl-abi-1.1, which is a virtual package
provided by perl-openssl-defaults.

debootstrap's pkgdetails_perl dependency resolution mechanism does not
consider virtual packages, so the dependency on perl-openssl-abi-1.1 is
basically ignored.

The expected outcome is for it to be resolved to perl-openssl-defaults,
which would then be installed along with the other packages and result in a
usable bootstrap.

I've reproduced this on v1.0.81ubuntu3.2 but from code inspection I can see
the same problem exists in current git - nothing examines Provides here.

Also reported at
https://bugs.launchpad.net/ubuntu/+source/debootstrap/+bug/86536