The libxcb package provides a replacement for the current Xlib interface. Some of its advantages include: - size: small library and lower memory footprint - latency hiding: batch several requests and wait for the replies later - direct protocol access: one-to-one mapping between interface and protocol - proven thread support: transparently access XCB from multiple threads - easy extension implementation: interfaces auto-generated from XML-XCB Xlib can also use XCB as a transport layer, allowing software to make requests and receive responses with both, which eases porting to XCB.