A nice practice that I try to follow it to always spell out what any Three Letter Acronyms (TLAs) the first time they are used. Then from that point onwards the simple TLA can be used.

In this case, BPF (shorthand for eBPF), stands for Extended Berkley Packet Filter. It’s a relatively new feature in the kernel that allows attaching small programs at certain “hook points” in the kernel (for example, when some syscall is called). These programs can pass information into userspace (like who is calling the syscall), and make decisions (whether to allow the call to proceed).

More info here https://ebpf.io/what-is-ebpf/