The ebpf site doesn’t mention that because expanding the abbreviation is not helpful for understanding ebpf. The name is representative the past of ebpf, not its present use or future.
In a sense eBPF as just some letters being a name is a better name than "extended Berkeley Packet Filter", just like DPRK is a better name than "Democratic People's Republic of Korea", since 75% of the words in the expanded acronym aren't even relevant or true.