For example, to install the semver extension, the client can be invoked as:
$ pgxn install semver
which would download and compile the extension for one of the PostgreSQL servers hosted on the machine and:
$ pgxn load -d somedb semver
which would load the extension in one of the databases of the server.
The client interacts with the PGXN web service and a Makefile provided by the extension. The best results are achieved with makefiles using the PostgreSQL Extension Building Infrastructure; however the client tries to degrade gracefully in presence of any package hosted on PGXN and any package available outside the extension network.