# Developer
Everything for reading, extending, and trusting the engine.
- **Symbol reference** — the exhaustive, per-symbol Doxygen rendition of the
headers: /api.
- **Architecture** — {doc}`How REAL works `, then the full
guided tour on /api/design.html
(Thompson NFA, Pike VM, prefilter, every fast path).
- **Coverage** — the coverage report: LLVM
source-based instrumentation, how to read it, and the full per-line report.
- **Performance** — the capability picture and how to read a number:
{doc}`Performance <../performance/index>`. Tables and the measurement
doctrine stay on GitHub:
[BENCHMARKS.md](https://github.com/RECHE23/real-regex/blob/main/docs/BENCHMARKS.md),
[MEASUREMENT.md](https://github.com/RECHE23/real-regex/blob/main/docs/MEASUREMENT.md).
- **Testing** — the test taxonomy and its gates:
[TESTS.md](https://github.com/RECHE23/real-regex/blob/main/docs/TESTS.md).
- **Development workflow** — the build/test harness (SciForge) and the
make-target taxonomy: {doc}`Development workflow `.
```{toctree}
:hidden:
:maxdepth: 1
how-it-works
workflow
```