Ok, so found more information on this from Microsoft (see below) - MICROSOFT, this is NOT good enough. I have to make sure I export the quality update information BEFORE it's applied or I can't see what went in? Furthermore, when I go to my Production environment which has NOT been updated yet, I can't see the quality update that has already been applied to my Training environment because a new quality update has been released that supersedes the one that was applied. You should NOT release Quality updates without having a way for customers to see what is included with the update, both before and after the update has been applied to an environment. Fix this and fast!
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How do I know what set of changes went into a quality update payload?
The following steps are a temporary solution as we continue to work on providing a better solution to identify the list of changes that go into a quality update payload.
Use KB# 745340 for the 10.0.28 Quality Update train and the related App version 10.0.1265.89.
In LCS, open the Environment details page for your sandbox.
In the Available Updates section, select View Update for the latest Quality Update build.
Export the build into a CSV or Microsoft Excel file.
In the exported file, sort the information based on time (oldest first) and then search for the KB number 745340 in the Update Id column. You should now be able to see the delta list of KBs.
Note
The export to a CSV or Excel file must happen before the environment is updated. Otherwise, you can use an environment with a similar configuration that doesn't have the update installed and follow the steps above.