The Perl module Module::Build::Pluggable adds pluggability for Module::Build and is required for Module::Build::Pluggable::PPPort (which was not in Debian), which in turn is required for HTML::Escape (which was also not yet in Debian), and which in turn is required for the v1.6.x version series of the LedgerSMB package.
I created the ITP (Intend To Package) bug #901882 to track working on adding it to Debian.
Besides the usual packaging issues, another was found that affected the operation the module tests under autopkgtest but not under a normal package build, caused by the t/*.t testing scripts not taking into account that "." (the 'current' directory) is no longer in @INC as of Perl version 5.26. This is hidden during a normal package build because that runs the tests under Test::Harness and that is currently set to enable the PERL_USE_UNSAFE_INC variable during the testing portion of the build. Enabled the ENV variable for autopkgtest as well by adding it to the debian/tests/pkg-perl/smoke-env file.
It was uploaded to New queue and then accepted into Debian at 12:00am on 27 July 2018.