Can somebody explane notation in schematics

[JoSta]

I have been checking schematics for my motherboard and have difficulties to understand it. I figured that i need to replace the component designated with PQB03 on the board. In the schematics I find two entries with different components, although they have almost similar specs. I could not find an explanation for the prefixes "G1G3@" or "G2@"
Can somebody help me?

[m1ch43lzm]

Usually the @ means "optional", "no stuff", or "option", as in alternate part number, depends on board manufacturer (Quanta, Compal, LCFC, inventec, Wistron, ...) and the context of the schematics

In your case it seems that PQB03 is AON7380, and the alternate part is AON7506, stick with the AON7380 as it has better specs (Id=24A vs 12A on the AON7506)
Check also the part number on the original MOSFET from your board, sometimes the schematics list one part, but the production board has a different part installed from factory

[truclacicr]

I suspect that G1, G2 and G3 refer to the Generation of the processor (or laptop?).

[m1ch43lzm]

Please post a link to the schematics to check (from the Schematics request sub forum)
Maybe the same laptop but with discrete/integrated graphics variants?