Why are some PHP extensions disabled by default in a XAMPP server?

There are a few PHP extensions (such as cURL) that are disabled by default in a XAMPP server.

What is the reason for that?

Is it mostly performance that's taken into consideration, is it security or is it so开发者_JS百科mething else?

Most likely it is because of performance reasons, to only load the necessary modules required by the user. It comes with the extensions installed because there is a relatively big likelihood the user would need the extension, but do not impose it upon them.

I'd say all of the above, with performance being the first reason. Why waste the time and memory to initialize something that you might never use?