I value integration flexibility and want to control or at least know exactly the spaced repetition algorithm I am using. Additionally, I believe a hosted servic

I value integration flexibility and want to control or at least know exactly the spaced repetition algorithm I am using. Additionally, I believe a hosted service without trustworthy end-to-end encryption is a no-go for personal knowledge management. So far I’ll stick with org-drill and Anki, it works for me (not using any add-ons).