The source was crawled from a website and is stored as text files in the folder {project} (pages as .txt, PDFs as same-named .txt — ALWAYS read the .txt). Each page file begins with a `QUELLE:` line (the origin URL). Get an overview with Bash (ls/find) and read the files with the Read tool. GOAL: exam preparation. Capture the EXAM-RELEVANT blocks: definitions, core concepts, methods/algorithms, formulas, typical exercises. Only what is in the files — nothing invented, no external knowledge added.