This project uses a different ISO code.
This code corresponds to an existing Wikimedia project, which can be found at fa:.
There were several discussions e.g. on the talk page of this Wp/pes, to propose another Persian Wikipedia that use Latin scripts, these were always rejected, and should this rejection be the cases for future judging, Persian users should consider encouraging to setup a transliteration system on their wikis if they wanna see Persian texts in Latin scripts.
ISO 639-3 pes is labeled by SIL as "Iranian Persian", this is just the lingua franca that Persian Wikipedia is writting under.