red54 wrote:

linux-libre-headers has replaced linux-headers, no need to conflict with it, because some other kernels' headers may also provide linux-headers.

In this case, is necessary linux-libre-headers to conflict with linux-headers due that linux-headers was built from non-free source code and if I will unblacklist linux-headers, we will have a freedom issue. Our distro doesn't accepts packages built from non-free source code. Even linux-libre-headers is provided from linux-headers, so it not should be a problem if you create a custom kernel and our kernels has custom headers for it.