The hexadecimal numbers are the important part there, the {"Series60ProductID"} is a text label which does not get displayed on Symbian devices from Nokia.
Most {"xy"} structures are localisable text labels in .pkg files, similar to the #-line you have fixed recently, that one is really getting displayed in the Application Manager as you have seen.
The complex structure comes from that they are localisable.
While a simple package looks like
Code:
#{"Hello World"},(0xE1234567),1,0,0
%{"Blah-blah"}
:"Blah-blah"
[0x101F7961], 0, 0, 0, {"S60ProductID"}
...
if someone adds multi-language support to the .pkg, all of them have to be localised:
Code:
&EN,HU
#{"Hello World", "Helló Világ"},(0xE1234567),1,0,0
%{"Blah-blah","Bla-bla"}
:"Blah-blah"
[0x101F7961], 0, 0, 0, {"S60 Product ID","S60 Készülékazonosító"}
...
So, if the given device is set to Hungarian language, the Application Manager will display "Helló Világ" as the name of the application, while devices with other language will display Hello World, as English is the common fallback language.
Series60ProductID is a similar displayable string, just it never gets displayed in reality.