SUMMARY
***
This command provides the following output:
$ kpackagetool5 --list-types

Package types that are installable with this tool:
Built in:
Addon Name           Service Type         Path                  
-------------------  -------------------  --------------------  
KPackage/Generic     KPackage/Generic     kpackage/packages/
KPackage/GenericQML  KPackage/GenericQML  kpackage/genericqml/

Provided by plugins:
kf.package: Invalid metadata for package structure "plasma_containmentactions"
kf.package: Invalid metadata for package structure "plasma_dataengine"
kf.package: Invalid metadata for package structure "plasma_lookandfeel"
kf.package: Invalid metadata for package structure "kwin_aurorae"
kf.package: Invalid metadata for package structure "plasma_wallpaper"
kf.package: Invalid metadata for package structure "plasma_theme"
kf.package: Invalid metadata for package structure "plasma_layouttemplate"
kf.package: Invalid metadata for package structure "plasma_generic"
kf.package: Invalid metadata for package structure "wallpaper_images"
kf.package: Invalid metadata for package structure "kwin_script"
kf.package: Invalid metadata for package structure "kwin_windowswitcher"
kf.package: Invalid metadata for package structure "plasma_applet"
kf.package: Invalid metadata for package structure "plasma_shell"
kf.package: Invalid metadata for package structure "kwin_effect"
kf.package: Invalid metadata for package structure "kwin_decoration"
kf.package: Invalid metadata for package structure "plasma_comic"
Addon Name                          Service Type               Path                    
----------------------------------  -------------------------  ----------------------  
                                    plasma_comic               
     Containment Actions                 plasma_containmentactions  
Face for the KSysguard Sensor Face  KSysguard/SensorFace       ksysguard/sensorfaces/
KWin Aurorae                        kwin_aurorae               
         KWin Decoration                     kwin_decoration            
             KWin Effect                         kwin_effect                
             KWin Script                         kwin_script                
    KWin Window Switcher                kwin_windowswitcher
        
        
        
        
For the record, I have found the propper output provided by Chris Holland 5 years ago:
Source https://www.reddit.com/r/kde/comments/61m10e/what_is_the_difference_between_plasmapkg/

$ kpackagetool5 --list-types
Package types that are installable with this tool:
Built in:
Addon Name           Service Type         Path                   
-------------------  -------------------  ---------------------  
KPackage/Generic     KPackage/Generic     kpackage/packages/
KPackage/GenericQML  KPackage/GenericQML  kpackage/packagesqml/

Provided by plugins:
Addon Name            Service Type               Path                        
--------------------  -------------------------  --------------------------  
Comic                 Plasma/Comic               plasma/comics/
Containment Actions   Plasma/ContainmentActions  plasma/containmentactions/
Data Engine           Plasma/DataEngine          plasma/dataengines/
  Generic               Plasma/Generic             plasma/packages/
 KWin Script           KWin/Script                kwin/scripts/
KWin Window Switcher  KWin/WindowSwitcher        kwin/tabbox/
 Layout Template       Plasma/LayoutTemplate      plasma/layout-templates/
Look and Feel         Plasma/LookAndFeel         plasma/look-and-feel/
Plasma Shell          Plasma/Shell               plasma/shells/
  Plasma Theme          Plasma/Theme               plasma/desktoptheme/
Plasmoid              Plasma/Applet              plasma/plasmoids/
  Wallpaper             Plasma/Wallpaper           plasma/wallpapers/
Wallpaper Images      Wallpaper/Images 


Following faulty output, this command throws an error:
$ kpackagetool5 --list --type kwin_script
kf.package: Invalid metadata for package structure "kwin_script"
Package type "kwin_script" not found
Listing service types: kwin_script in /home/v/.local/share/

Finally, this command is successful
$ kpackagetool5 --list --type KWin/Script

***



SOFTWARE/OS VERSIONS

Operating System: KDE neon Testing Edition VM
KDE Plasma Version: 5.25.3
KDE Frameworks Version: 5.97.0
Qt Version: 5.15.5
Kernel Version: 5.15.0-41-generic (64-bit)
Graphics Platform: X11
+
Operating System: Manjaro Linux
KDE Plasma Version: 5.24.6
KDE Frameworks Version: 5.96.0
Qt Version: 5.15.5
Kernel Version: 5.18.10-1-MANJARO (64-bit)
Graphics Platform: X11

ADDITIONAL INFORMATION