Some of the highlights:
- GCC is no longer installed by default on architectures where clang(1) is the default compiler.
- Unbound has been imported to the base system as the local caching DNS resolver.
- BIND has been removed from the base system.
- make(1) has been replaced with bmake(1), obtained from the NetBSD Project.
- pkg(7) is now the default package management utility.
- pkg_add(1), pkg_delete(1), and related tools have been removed.
- Major enhancements in virtualization, including the addition of bhyve(8), virtio(4), and native paravirtualized drivers providing support for FreeBSD as a guest operating system on Microsoft Hyper-V.
- TRIM support for Solid State Drive has been added to ZFS.
- Support for the high-performance LZ4 compression algorithm has been added to ZFS.
See the full 10.0-RELEASE announcement here.