https://techbase.kde.org/Development/Tutorials/Plasma2/QML2/API
states
What Is a Declarative Plasmoid?
To denote that this Plasmoid is a Declarative widget, ensure that in the metadata.desktop file there is this line:
X-Plasma-API=declarativeappletscript
What follows is a description of the Plasma declarative classes instantiable from QML.
but what does this actually mean for me, the developer of a Plasmoid? I’m rather new to QML.