Comment 6 for bug 1821502

@Holger

You can see label exactly like filenames.
Labels are living in sheets, like files in folders.

Because Kicad supports hierarchies, and especially complex hierarchies (having sub-schematics instantiated more than once) labels, like files, have a full name (similar to a full file name)

The label "mylabel" inside the root sheet has the full name /mylabel, like the file "myfile" in the root directory is actually /myfile.
The label "mylabel" inside the sheet "sample_sheet" has the full name /sample_sheet/mylabel, like the file "myfile" in "/sample_sheet" folder is actually /sample_sheet/myfile.

This is mandatory to avoid collision between label names.

However global labels are not attached to a specific sheet, therefore have no path.

the global label "GND" for instance has no path, therefore any label called "GND" in any sheet is connected to any other "GND", regardless the sheet where it is living.