There are EFI firmware updates apparently for all Mojave-capable Mac models, which I have now entered in my article listing current EFI firmware versions.
Apple’s release notes give few clues as to what has changed, although there are plenty of security fixes.
The macOS Mojave 10.14.5 update is another hefty one, amounting to 2.5-2.8 GB of download, slightly smaller than the previous update to 10.14.4, and installs over 70,000 items taking over 6 GB of disk storage.
