Only the newest, released Xcode is exclusively available from the Mac App Store. No Apple products are ever released through package managers (e.g. homebrew, macports, etc.), or non-Apple servers. Xcode 9, and its corresponding Command Line tools require Sierra 10.12.6 or later.
Xcode 10.2 Download
XCode 8 El Capitan Mac OSX 10.11.6 Part #1. Xcode 10 is available in the Mac App Store and includes SDKs for iOS 12, watchOS 5, macOS 10.14, and tvOS 12. Xcode 10 supports on-device debugging for iOS 8 and later, tvOS 9 and later, and watchOS 2 and later. Xcode 10 requires a Mac running macOS 10.13.6 or later. General New Features.
Latest Xcode and Command Line tools for El Capitan:
- Xcode 8.2.1
- Command Line Tools (macOS 10.11) for Xcode 8.2 (Dec. 11, 2016)
You appear to have these items installed.
Xcode 10.11
These are available through either a free, or paid developer account. You need to allow Xcode to install optional components when you run it, and encounter the related dialog. The above bulleted items are what I have installed.
Xcode 10 Download
Optional documentation installation is available via Xcode : Preferences.
I have Xcode 8.2.1 installed.
xcode-select --version : 2343
Xcode 10 Download For Mac
xcode-select -p : /Applications/Xcode.app/Contents/Developer
gcc --version: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/ usr/bin
Xcode 10.15
clang --version: same location
Oct 16, 2017 3:17 AM