CAPS
From OpenSimulator
CAPS is short for Capabilities.
Often referred to as Region Capabilities.
The CAPS a region supports are most often used by viewers to provide support for features such as media, voice, etc.
What are caps?
the capabilities concept is based on the "password" being a URL,
so basically a URL is created to accept a specific message from a specific client,
and simply knowing the URL constitutes right of access, these urls are ephemeral,
the login server obtains a "seed" cap from the sim the user is sent to,
the viewer accesses the seed cap to get all other caps,
not every sim must provide every cap, a sim without a voice module loaded may not provide voice caps,
a sim without media on a prim would not have media caps,
so the seed cap response allows the viewer to adjust it's UI to the capabilities of the sim,
additional info can be obtained by invoking some caps, like sim options,
when you cross or teleport the sim you're departing gets a new seed from the sim you're going to and gives it to you so you can contact the new sim.
obviously, when crossing you already have them because you have an open child agent connection while sims talk amongst each other,
most of the talking is done to the client. Sims do **NOT** talk to each other via caps
