Job description (JD)
The document stating a role's responsibilities and requirements. The responsibilities section usually carries more truth than the requirements list.
What it tells you about a developer
A clean, short, internally consistent job description signals an engineering team that knows what it needs. A long contradictory one predicts a search that gets renegotiated partway through.
A technical job description usually has four parts: a company blurb, responsibilities, required skills, and nice-to-haves. The requirements list is the least reliable section, because it accumulates wishlist items from several authors. Read the responsibilities first, then use them to decide which requirements are load-bearing.