Putting tldr; at the bottom defeats purpose of tldr.

Guessing this is BPF https://en.wikipedia.org/wiki/Berkeley_Packet_Filter But, reader shouldn't have to guess. That is the link that should be in your Introduction. Just after tldr;

Not the original BPF, but its successor in the Linux kernel called eBPF [1]. eBPF's virtual machine has additional registers, and crucially, eBPF programs can make some syscalls, which BPF programs can't.

[1]: https://lwn.net/Articles/740157/