Here is a testing slackbuild for hplip-plugin-3.25.2 package

[Acknowledgements]
When creating the script, I used Arch Linux's PKGBUILD as a reference.
Thanks to Arch linux.


hplip-plugin.SlackBuild
[code]
#!/bin/sh

# Slackware build script for hplip-plugin

# Copyright 2025 JW(Shinichi Abe) <shin1.abe@nifty.com>
# All rights reserved.
#
# Redistribution and use of this script, with or without modification, is
# permitted provided that the following conditions are met:
#
# 1. Redistributions of this script must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR IMPLIED
#  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
#  EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
#  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
#  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
#  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
#  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
#  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

PRGNAM=hplip-plugin
VERSION=${VERSION:-3.25.2}
BUILD=${BUILD:-1}
TAG=${TAG:-jw}
PKGTYPE=${PKGTYPE:-txz}

if [ -z "$ARCH" ]; then
  case "$( uname -m )" in
    i?86) ARCH=i586 ;;
    arm*) ARCH=arm ;;
       *) ARCH=$( uname -m ) ;;
  esac
fi

CWD=$(pwd)
TMP=${TMP:-/tmp/SBo}
PKG=$TMP/package-$PRGNAM
OUTPUT=${OUTPUT:-/tmp}

if [ "$ARCH" = "i586" ]; then
  SLKCFLAGS="-O2 -march=i586 -mtune=i686"
  LIBDIRSUFFIX=""
elif [ "$ARCH" = "i686" ]; then
  SLKCFLAGS="-O2 -march=i686 -mtune=i686"
  LIBDIRSUFFIX=""
elif [ "$ARCH" = "x86_64" ]; then
  SLKCFLAGS="-O2 -fPIC"
  LIBDIRSUFFIX="64"
else
  SLKCFLAGS="-O2"
  LIBDIRSUFFIX=""
fi

set -e

rm -rf $PKG
mkdir -p $TMP $PKG $OUTPUT
cd $TMP
rm -rf $PRGNAM
mkdir $PRGNAM
unzip $CWD/hplip-${VERSION}-plugin_run.zip
sh hplip-${VERSION}-plugin.run --target $PRGNAM --noexec
rm hplip-${VERSION}-plugin.run
cd $PRGNAM

chown -R root:root .
find -L . \
 \( -perm 777 -o -perm 775 -o -perm 750 -o -perm 711 -o -perm 555 \
  -o -perm 511 \) -exec chmod 755 {} \; -o \
 \( -perm 666 -o -perm 664 -o -perm 640 -o -perm 600 -o -perm 444 \
  -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;

  install -Dm644 -t "$PKG/usr/share/hplip" plugin.spec
  install -Dm644 -t "$PKG/usr/share/hplip/data/firmware" hp_laserjet_*.fw.gz
  install -Dm755 -t "$PKG/usr/share/hplip/fax/plugins" fax_marvell-"$ARCH".so
  install -Dm755 -t "$PKG/usr/share/hplip/prnt/plugins" hbpl1-"$ARCH".so
  install -Dm755 -t "$PKG/usr/share/hplip/prnt/plugins" lj-"$ARCH".so
  install -Dm755 -t "$PKG/usr/share/hplip/scan/plugins" bb_*-"$ARCH".so

  install -Dm644 -t "$PKG/usr/share/licenses/$PRGNAM" license.txt

  # Create hplip.state used by hplip-tools
  cat << EOF > hplip.state
[plugin]
installed = 1
eula = 1
version = $VERSION
EOF
  install -Dm644 -t "$PKG/var/lib/hp" hplip.state

# Create symlinks
mkdir -p $PKG/usr/lib${LIBDIRSUFFIX}

  find "$PKG/usr/share/hplip" -type f -name "*.so" | while read -r f; do
    lib_dir="${f%/*}"
    lib_name="${f##*/}"
    ln -vsf "$lib_name" "$lib_dir/${lib_name%%-*}.so"
  done

# Note: to check the install, perform: hp-diagnose_plugi

find $PKG -print0 | xargs -0 file | grep -e "executable" -e "shared object" | grep ELF \
  | cut -f 1 -d : | xargs strip --strip-unneeded 2> /dev/null || true

find $PKG -name perllocal.pod \
  -o -name ".packlist" \
  -o -name "*.bs" \
  | xargs rm -f

mkdir -p $PKG/usr/doc/$PRGNAM-$VERSION
cp -a \
  *.txt $PKG/usr/doc/$PRGNAM-$VERSION
cat $CWD/$PRGNAM.SlackBuild > $PKG/usr/doc/$PRGNAM-$VERSION/$PRGNAM.SlackBuild

mkdir -p $PKG/install
cat $CWD/slack-desc > $PKG/install/slack-desc

cd $PKG
/sbin/makepkg -l y -c n $OUTPUT/$PRGNAM-$VERSION-$ARCH-$BUILD$TAG.${PKGTYPE}

slack-desc
[code]
# HOW TO EDIT THIS FILE:
# The "handy ruler" below makes it easier to edit a package description.
# Line up the first '|' above the ':' following the base package name, and
# the '|' on the right side marks the last column you can put a character in.
# You must make exactly 11 lines for the formatting to be correct.  It's also
# customary to leave one space after the ':' except on otherwise blank lines.

            |-----handy-ruler------------------------------------------------------|
hplip-plugin: hplip-plugin (HPLIP binary plugins)
hplip-plugin:
hplip-plugin: Binary plugin for HPs hplip printer driver library
hplip-plugin:
hplip-plugin:
hplip-plugin: HOME:https://developers.hp.com/hp-linux-imaging-and-printing/plugins
hplip-plugin:
hplip-plugin:
hplip-plugin:
hplip-plugin:
hplip-plugin:

hplip-plugin.info
[code]
PRGNAM="hplip-plugin"
VERSION="3.25.2"
HOMEPAGE="https://developers.hp.com/hp-linux-imaging-and-printing/plugins"
DOWNLOAD="https://developers.hp.com/system/files/2025-03/hplip-3.25.2-plugin_run.zip"
MD5SUM="dfcb94f1caecaaf2eecdfef953de2606"
DOWNLOAD_x86_64=""
MD5SUM_x86_64=""
REQUIRES="%README%"
MAINTAINER=""
EMAIL=""



===