Para los que no sepan lo que es curl
Curl is a command-line tool for transferring data specified with URL syntax. Find out how to use curl by reading the curl.1 man page or the MANUAL document. Find out how to install Curl by reading the INSTALL document.
libcurl is the library curl is using to do its job. It is readily available to be used by your software. Read the libcurl.3 man page to learn how.