Definition
Plain language
A widely used free software library for reading and writing XML files.
As stated in the literature
A C library for parsing and manipulating XML; appears as a target codebase in automated vulnerability-discovery work, where its complex internal type hierarchy made some confirmed bugs costly in tokens to surface.
Why it matters: Because it is so widely embedded in other software, finding and fixing flaws in it protects a huge range of downstream systems.
For example, an automated bug-hunting tool might comb through this XML library and confirm a flaw buried deep in its tangled internal types.
Heard on the show
“Per-bug cost ranges from less than a million tokens — that's mupdf — up to twenty-nine million, which is libxml2.”Episode 014 — Why a Constrained Pipeline Beat a Full Coding Agent at Finding Bugs 30-to-1