OK, it says this on the projectpokemon.org/events page:
Generation V events are in pgf file format which contains the card and the corresponding gift. Generation IV events files are in pcd format (for the Wonder Card) and pgt format (for the gift itself).
You can use Pokegen to insert the files into your game’s sav file directly, or generate AR codes.
It is not recommended to use Pokesav (Japanese OR translated versions) for non-Japanese games and events as it has many errors in handling some special characters outside of the Japanese character set.
I've seen how to insert the files into a .sav file with Pokesav, but it says not to use it. I've become fairly proficient in using Pokegen to edit Pokemon and .sav files. However, with these event Pokemon files, it seems to want to use the Mystery Gifts tool in Pokegen, which looks like it's meant for exporting .pgf or .pcd files or creating a .pkm file for the event Pokemon instead of activating the event to receive the Pokemon and Wonder Card ingame from the delivery man. Is there an actual way of using Pokegen to insert these files directly into the .sav file and/or generate AR codes, and are there detailed instructions and/or tutorial how to do so? What about Pokemon Mystery Gift Editor, is that the way to go for these event Pokemon files rather than Pokegen or Pokesav?