This will be same for the European Union Green Certificate (DGC): https://ec.europa.eu/health/ehealth/covid-19_en
The German app and implentation will be on GitHub too: https://github.com/Digitaler-Impfnachweis
The German app and implentation will be on GitHub too: https://github.com/Digitaler-Impfnachweis
The apps and integration server are here: https://github.com/eu-digital-green-certificates
The schema and business rules are here: https://github.com/ehn-digital-green-development
Come join us if you're interested in taking a look, it's quite interesting :)