The xmake package repository files might be useful also for people interested in making their own package manager, or even installing by hand.
Here is the package information for autoconf, for instance:
https://github.com/xmake-io/xmake-repo/blob/master/packages/...
It has download links, checksums for specific versions, and the Lua syntax seems easy to parse.
The package for NanoVG however, does not indicate anywhere that you need the GLEW and GLFW libraries: