The MacBook Pro "Core i7" 2.6 15-Inch (Integrated Graphics/Iris Only - Late 2013 Retina Display) is a built-to-order version of the MacBook Pro "Core i7" 2.0 15-Inch from the same period, though it's also documented as a separate model for clarity. The processor is the only component that differs between them.
It's important not to confuse this model with the MacBook Pro "Core i7" 2.6 15-Inch (Dual Graphics - Late 2013 Retina Display), which is equipped with two graphics processors instead of one.
This model packs a 22 nm "Haswell/Crystalwell" 2.6 GHz Intel "Core i7" processor (4960HQ) with four independent cores on a single chip and a 6 MB shared level 3 cache. It has 8 GB of onboard 1600 MHz DDR3L SDRAM (upgradable to 16 GB at purchase), 256 GB of PCIe-based flash storage, and an integrated Intel Iris 5200 Pro graphics processor with 128 MB of "Crystalwell" embedded DRAM. It also includes an integrated 720p FaceTime HD webcam and a high-resolution 15.4" LED-backlit 2880x1800 (220 ppi) "Retina" display, all in a chassis that weighs under 4.5 pounds (2.02 kg) and lacks an optical drive.
Connectivity includes 802.11ac Wi-Fi, Bluetooth 4.0, two USB 3.0 ports, two "Thunderbolt 2" ports, an HDMI port, an audio in/out port, and an SDXC card slot.
Additionally, this model comes with a backlit keyboard, a "no button" glass "inertial" multi-touch trackpad, a "MagSafe 2" power adapter, and a sealed internal battery with an Apple-estimated 8 hours of life.
Compared to its predecessor, this version has a nearly identical external case but features a more efficient processor and architecture for improved battery life, plus faster storage, Wi-Fi, and connectivity.