the pokémon data structure has been forwards-compatible since November 21, 2002, over twenty years
this is not as old as javascript, css, or xml, but it is roughly as old as the first JSON and YAML libraries
the previous pokémon data structure, which IS as old as (standardized) javascript, was later made forwards-compatible (with the virtual console releases of red and blue on the 3DS), but since there is no way to get a pokémon from a game boy game into the current ecosystem i’m saying that the original pokémon data structure as present in the original physical games still doesn't qualify
but you COULD argue it does
you CAN
a) play pokémon in an emulated version of games released prior to the publication of ECMAScript 1.0, and
b) transfer those pokémon into a game released in 2022 and use them like any other mon
