More than ever, Mac is the computer people love to use. And one of the biggest reasons is OS X. It’s what makes a Mac a Mac. With OS X, it’s simple to do amazing things and delightful to do all the everyday things. OS X El Capitan builds on the groundbreaking features and beautiful design introduced in OS X Yosemite, refining the experience and improving performance in lots of little ways that make a big difference. OS X El Capitan — it takes the Mac experience to new heights.

Homepage : http://www.apple.com/

Note : 

- This is the original Image from Mac App Store.

Full 10.11.3 (Build 15D21) installer with a dummy receipt, zipped with Entropy

I recommend unzipping with the default OS X Archive Utility for the best compatibility (Right Click > Open With... > Archive Utility)

"Install OS X El Capitan.app/Contents/SharedSupport/InstallESD.dmg"
MD5: 24c74acc4779b32a01024348c00892dc
SHA1: e4311d93127d0668372b32e5342f3b455b6bc9bd

Can be made into a bootable usb drive with DiskMaker X or createinstallmedia