I'm confused by your comments about Qt5, so I'll wait to see what you mean. However, this copyright refers not to the plist file, but to the GCS program, i.e. the binary executable. 

I'm unsure about the nature of copyright for binary files, but I suspect it would belong to the group that compiled it, independent of the source code. So the copyright is either ours, and is correct as modified, or it needs to be attributed to Nokia, OP, and TL.

Honestly, I don't think it's important there at all, and it can be removed if that makes things easier.