Available under a OSS compliant license (https://opensource.org/license/UPL), it's a shame that this completely user space implementation based on BPF hasn't got wider attention. Looking at the activity on dtrace-devel it seems like it's actively maintained by a team of dedicated developers.

The Linux "native" alternative bpftrace is fantastic but it's not practical to use it in an embedded environment because it pulls in llvm-libs.