The Reposado software replicates key functions of the Mac OS X's server's software update service. The software consists of a set of tools that were written in Python and that accurately replicate key functions in a way that doesn't cause crashes, lag, stalls, or confused commands. It has a BSD licence.
Host An Apple Software Update Server Locally
You may host your Apple software update sever locally on the operating system and hardware of your choice (within reason). Most would call Reposado a free piece of software, but it actually has a BSD licence, which may end up costing a user and/or developer money if the (albeit permissive) rules are broken in a severe way. The tool is available to download from Apple servers, which is handy if you want the updates. It is even able to function as a web server that is able to deliver the updates to client machines.
A Flexible Tool For People Who Need Updates
With the Reposado tool, you are able to do locally what you usually have to do via the Apple servers. There are plenty of reasons, both naughty and nice, why a company would wish to use this tool. Suffice it to say that it is both powerful and uniquely useful so long as it is maintained and updated correctly as time goes one.