Looks like it is the center of all parts, but the initial bounding box of the prefix is included as part of the group when the center of the group is calculated.
 

Confirmed (I think)... Should be as simple as swapping two lines of code ;)

@vlrm.prjct
btw. what you want is not only setting the group origin to its proper center (Bugfix), but maybe also setting a custom origin for the group, right? You can use this script to set the origin/center of the selected group to the current origin of the editor. That probably should be a separate Feature Request.

// Set selected Group-Origin to Editors Origin
group = api('getShape',{id: api('getSelectedIds')});
source = api('getSource', {type: "json"});
if(group?.head?.x !== undefined && source?.canvas?.originX !== undefined) {
	group.head.x = source.canvas.originX;
	group.head.y = source.canvas.originY;
	api('updateShape',{ shapeType: 'pcblib', jsonCache: group });
}

Ahio @andreasbernhofer,

Thank you!

Yep you are right.

For me it is a bug.
Why should the prefix label be part of a group? The point is, if you move, hide or rename the prefix, the origin doesn't change.

Your second post saves my life ... \o/ ... and works pretty neat.
Thank you again !

Maybe someone will stumble across this post and try to run this snippet.
But it won't work because of the ( in some cases ) unsupported questionmark syntax, which will end in a syntax error.

The fixed version ( if condition ) looks like this:

if(
    (group && group.head && group.head.x !== undefined)
    && (source && source.canvas && source.canvas.originX !== undefined)
) {
	group.head.x = source.canvas.originX;
	group.head.y = source.canvas.originY;
	api('updateShape',{ shapeType: 'pcblib', jsonCache: group });
}