Org-fc is a spaced repetition system implemented as an Emacs package for org-mode. It allows users to mark org-mode headlines as flashcards and review them using spaced repetition algorithms (SM2 or FSRS). The system features multiple card types (normal, double, text-input, cloze, vocab), efficient indexing via AWK scripts with caching, a dashboard for statistics, and optional extensions like audio playback and key-binding hints. The architecture is modular with clear separation between core functionality, review logic, card types, spacing algorithms, and utilities.