How can you tell which upgrades and updates your Mac has downloaded and installed? If you wish, you can rummage through those listed in System Information’s Installations. I’d prefer to browse something a bit more selective and ordered: SystHist.
This new version now handles RSRs in its three panels.
At the left is a hierarchical listing of each release of macOS, and all the updates installed in each. One quirk in this list is that it also includes any older installers you may also have downloaded, perhaps for use on an external disk.
In this case, at the foot you’ll see the 13.3.1 update, followed by two XProtectPayloads for XProtect Remediator, and the RSR in between.
In the centre panel is a chronological list of the same macOS and security updates, here with the most recent at the top.
The right panel lists those macOS and related updates that came with a BoM (Bill of Materials). Click on any of those and a floating window lists their full contents.
SystHist version 1.18 is now available from here: systhist118
from Downloads above, from its Product Page, and via its auto-update mechanism. Because of the limitations of Xcode, this now requires High Sierra or later.