Symbol Editor: Difference between "duplicate Symbol" and "new Symbol" --> "derive from"

[LangerJan]

In KiCad symbol editor I do not understand the difference between

• new symbol → derive from existing symbol
• duplicate symbol

The first one creates an italic name entry in the library.
The symbol graphic in this derived symbol can not be edited.

For my original symbol I have added several new attribute classes (MFG-Name / MFG-part#, …).
I want to derive many new symbols (representing actual components) by having the same symbol, but adding a fixed component value and the MFG data for this part in my attribute fields.

But when I generate a new symbol and select derive from the above original symbol all user created attributes classes are missing. I only find the Kicad default attributes (Reference, Value, Footprint, Datasheet). This is annoying since I have to define the attribute names all over again.

When I just *duplicate the original symbol all the attributes (names and values) are still present. But then it’s an independant symbol that contains it’s own symbol graphic.

Is there a reason why the user defined attribute names and values are not copied for new symbol → derive from existing symbol ?

Could somebody please explain the indended use case for the above two methods of copying a symbol.

I am using KiCad 7.0.8 release build on Windows 10.
I am aware that the pro solution would be to use the new database library feature. But this step is too big for me right now.

[mf_ibfeew]

“derived” symbols are special symbols. Try to read the manual (section “Symbols”) and search for the word “derived”: Schematic Editor | 7.0 | English | Documentation | KiCad.

copy/pasting (==duplicating) creates a complete new, independant copy from the source symbol.

new symbol–>derive from existing creates a new symbol with a “Link” to the original symbol graphics. If you change the graphics of the original symbol, all derived symbols also change.
Regarding the custom data fields: the derived symbols share all original data fields, but they are not shown in the symbol properties dialog in the symbol editor. But if you add the derived symbol to your schematic these “original” data fields show up in the symbol properties.

So deriving a symbol from another symbol is definitely a different usecase than copy/pasting (duplicate) a symbol. It depends: Do you explicitly want to share the symbol graphics (including all pins) between source-symbol and derived symbol or do you want completely independant symbols?