About the security content of macOS Mojave 10.14.3 Supplemental Update
Installing macOS Mojave 10.14.3 Supplemental Update on your Mac updates the build number of macOS to 18D109. This build contains the security content described in this article. If you update to macOS Mojave 10.14.3 and your macOS build is not 18D109, make sure you also install the Supplemental Update.
