pli (Iron Spring PL/I Compiler for Linux)

pli is a compiler for the PL/I programming language, which implements
most of the "PL/I General-Purpose Subset" (aka "Subset G"). The
compiler itself is closed-source, but it may be used and copied
freely. The runtime library (libprf.a) is released under the GNU LGPL,
so that programs linked with it can be distributed freely.

The package ships with extensive documentation. Also, see
README_SBo.txt for Slackware-specific details.

There's no way to build or run this on aarch64, or anything else but
x86 and x86_64.