You are correcting and completing the subblocks of ONE block of the topic "{topic}" — strictly from the source excerpts.

BLOCK: {block}

{source}

TASKS:
{auftraege}

Rules:
- Work ONLY from the excerpts. Invent no values, compute nothing yourself.
- For corrections: return the subblock with its EXACT title and the complete corrected fact set.
- For gaps: ONE new subblock per gap, atomic, GERMAN title (max ~10 words), fully backed — if the excerpts don't support it, leave it out entirely.
- Field rules as always: key_points 1–3; cited_facts only backable with location; example_idea free; level beginner|advanced|expert; relevance relevant|peripheral. All content in GERMAN.

Reply with ONLY the JSON — no code fences, no other text. EXACTLY this format (empty list if nothing is backable):
{{"subs": [
  {{"title": "…", "level": "…", "relevance": "…",
    "key_points": ["…"], "prerequisites": "…", "hurdles": "…",
    "cited_facts": [{{"text": "…", "source": "…"}}], "example_idea": "…"}}
]}}
{extra}
