
Here is the log of HP device manager which by default does not install the needed dependency.
$this->bbcode_second_pass_code('', '
[corey@corey-pi4 ~]$ hp-toolbox
HP Linux Imaging and Printing System (ver. 3.21.2)
HP Device Manager ver. 15.0
Copyright (c) 2001-18 HP Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.
error: No module named 'PyQt5'
')
After installing python-pyqt5 the issue is fixed.
$this->bbcode_second_pass_code('', '
[corey@corey-pi4 ~]$ hp-toolbox
HP Linux Imaging and Printing System (ver. 3.21.2)
HP Device Manager ver. 15.0
Copyright (c) 2001-18 HP Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.
HP Linux Imaging and Printing System (ver. 3.21.2)
System Tray Status Service ver. 2.0
Copyright (c) 2001-18 HP Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.
HP Linux Imaging and Printing System (ver. 3.21.2)
HPLIP upgrade latest version ver. 1.0
Copyright (c) 2001-18 HP Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.
error: HPLIP upgrade is disabled by Archlinux for security reasons, see https://bugs.archlinux.org/task/38083 - if you like to upgrade HPLIP, use the Archlinux software package manager pacman.
Done.
')
I believe by not including the package as a necessary dependency it will break the user experience and cause confusions on why it is not working.