Please go to https://github.com/pr2database/pr2-primers-shiny for detailed information about the database and Shiny application source code.
Vaulot, D., Mahé, F., Bass, D., & Geisen, S. (2021). pr2-primer : An 18S rRNA primer database for protists. Molecular Ecology Resources, in press. DOI: 10.1111/1755-0998.13465