It is used as a dependency of mdevd, which has been suggested somewhere as a potential partial replacement for udev in server installations. Another reverse dependency is s6, an init and service management system similar to runit. There is also a httpd server called tipidee on skarnet, but I do not know whether it constitutes any improvement over free nginx.

The library as such builds nicely here with 0.4.2 but I did not yet install it because I could not see whether it is actually useful in the current situation of hyperbola.