Apple has pushed an update to the data used by TCC, the privacy protection system in macOS 10.14 Mojave, bringing its version number to 17.0, dated 5 June 2019.
Apple provides no details as to what changes this update brings, and doesn’t even describe what this data does. However, this update replaces the existing ‘allow applications’ list in the database, which is loaded whenever your Mac starts up. As this data file is specific to Mojave, those still using earlier versions of macOS will not receive any such update: this is Mojave-only.
Examination of the changes reveals that this should address privacy protection issues with some additional third-party software, including Steam, Wacom tablets, and some Adobe products.
You can check whether this update has been installed by opening System Information via About This Mac, and selecting the Installations item under Software.
A full listing of security data file versions is given by LockRattler and SystHist for El Capitan, Sierra, High Sierra and Mojave, available from their product page. If your Mac has not yet installed this update, you can force an update using LockRattler, or at the command line.
I have updated the reference pages here which are accessed directly from LockRattler 4.2 and later using its Check blog button.
Thanks to Al for keeping me up to date while I was asleep.