X.Org Server refers to the free and open source implementation of the X Window System stewarded by the X.Org Foundation that includes not only the display server but also the client libraries (like Xlib and XCB), developer and user tools, and the rest of the components required to run an entire X Window System architecture.The services with which the X.Org Foundation supports X Server include the packaging of the releases; certification (for a fee); evaluation of improvements to the code; developing the web site, and handling the distribution of monetary donations.