Hi,
you've created the batman_adv.h for the netlink interface of batman-adv and you've used the GPL-2-only license header. It is a header which is installed for userspace programs and will maybe be used for things which have a different license then the GPL-2. So it would maybe better for these use cases to have clear statement that they can use it freely. This can for example be done with a more liberal license like the ISC [1] (like in nl80211.h [2]).
What do you think about a license change? If you agree then I would like to propose a patch which requires a reply by you with an "Acked-by: ...".
Kind regards, Sven
[1] https://en.wikipedia.org/wiki/ISC_license [2] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/include...