mod_xml_curl uses the curl library, the same library behind the curl executable utility ( https://curl.haxx.se/ great documentation!), to get a snippet of XML from a webserver in response to an internal FreeSWITCH request.
In its base configuration FreeSWITCH at startup reads its XML configuration from filesystem. FreeSWITCH XML configuration is composed by a couple of XML files that "include" many other XML files. The inclusion mechanism, and the inherent structure in XML files, results in one very big XML tree to be built into FreeSWITCH memory.
Each time FreeSWITCH needs to know something about its own configuration (module parameters, dialplan, User Directory, and so on), FreeSWITCH uses its internal XML tools to query the big in-memory XML tree. From each one of those queries, that in a busy server can be thousands at a second, FreeSWITCH receive an XML snippet response, containing the relevant data. The query/response is immediate and extremely light, like a binary...