I was wondering what the goal of the project is. The README is not very clear on it, but the implementation document [1] does state design goals:

- Small memory usage within a fixed-sized memory region — no mallocs

- Practical for small scripts (extension scripts, config files)

- Concise source — less than 1000 loc

- Portable ANSI C (Windows, Linux, DOS — 32 and 64bit)

- Simple and easy to understand source

- Simple and easy to use C API

[1] https://github.com/rxi/fe/blob/master/doc/impl.md