Yalibs is a gathering place for simple and independent implementations of various types of libraries. From the contributions graphs, you may think that the libraries are unmaintained, but this is not so. The libraries are just simple and once implemented they typically don't need much maintenance other than the occational language version upgrade (we strive for no non-standard dependencies, so we don't even need to update the dependencies). If you have an issue with one of the libraries, feel free to submit an issue or pull request on the respective repository.
You can find some documentation at yalibs.dk, which is maintained in the yadocs repo.