Constant PDF_ML_COMPILED 

pub const PDF_ML_COMPILED: bool = true;

Which PDF conversion this build compiled in: the full ML pipeline (pdf feature), the pure-Rust text-layer path (pdf-text, the wasm32 build), or neither. Compile-time facts, exported so downstream crates (whose own features can’t see this crate’s) can branch — e.g. docling-wasm’s host tests, where workspace feature unification may pull pdf in.