If one integrates content (code, fonts, etc.) that is published under GPL in a software application that is published under GPL as well, how to correctly attribute the authors of the integrated parts? In detail it would be interesting to know
The GPL does require you to keep any existing copyright notices:
- You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you [...] keep intact all the notices that refer to this License and to the absence of any warranty [...]
The GPL also recommends adding a notice to each file:
Copyright (C) yyyy name of author - This program is free software[...]
From my reading of the GPL, if the software you modify contains such notices, which is likely, you must preserve them. This effectively attributes the original author.
However, as far as I can see, there is no requirement to have a list of acknowledgements (as is customary in scientific papers), which lists all the software you used.
How to attribute parts that are integrated in source form? (Where licence information is given in the file header)
If you keep the original file header (and possibly add to it), that should be enough.
How to attribute parts that are integrated in binary form?
As far as I can see, there is no additional attribution required for distribution in binary form. The GPL requires you to supply the source code along with the binary form, so the attribution in the source code will be available.
To comply with the licence you must attribute in the way the licence tells you to. If the licence is not specific the a readme text file included with the package with the attributions consolidated would be fine.
