苹果会定时在不通知用户的情况下，在后台想所有的OSX系统发送更新，下面列出这些部分已知的系统文件：
Latest version: 747, 1 June 2016.
This is support data for /System/Library/PrivateFrameworks/CoreSuggestions.framework and goes into /System/Library/Intelligent Suggestions, to be used in various travel features.
Latest version: 8, 1 May 2016.
This is support data for /System/Library/PrivateFrameworks/CoreLSKD.framework and goes into /usr/share/kdrl.bundle for internal use.
Latest version: 90, 14 June 2016.
This is an SQLite database which is placed in /private/var/db/gkopaque.bundle/Contents/Resources/gkopaque.db to provide blacklists and whitelists for Gatekeeper’s security system, which checks the code signatures of apps.
Latest version: 3.30.1, 5 April 2016.
This is a list of kernel extensions (KEXTs) which will be excluded at startup, and is stored in /System/Library/Extensions/AppleKextExcludeList.kext.
There have been some glitches in this: version 3.28.1 of 26 February 2016 was a dud, and was replaced by 3.28.2 on 28 February 2016, because it excluded a key Ethernet driver for some recent models.
Latest version: 1.8, 29 April 2016.
This is the settings for Apple’s Malware Removal Tool /System/Library/CoreServices/MRT.app and goes into that app, so that it can remove any malware which OS X detects.
Latest version: 1.0, 18 May 2016.
These are the whitelists and blacklists used by XProtect. They go into /System/Library/CoreServices/XProtect.bundle/Contents/Resources/XProtect.meta.plist and
/System/Library/CoreServices/XProtect.bundle/Contents/Resources/XProtect.plist.
Latest version 4.17, 2 June 2016.
This is, of course, not security related, and only of relevance when using Chinese language support on your Mac.
Although this has not been updated since the original release of El Capitan, I include it here for completeness. These settings are placed in /System/Library/PrivateFrameworks/SystemMigration.framework and /System/Library/Sandbox/Compatibility.bundle, for use by Migration Manager.
参考：https://eclecticlight.co/2016/05/04/silent-night-el-capitans-security-settings-files/