Used SK 1.15 from the HFS+(HDD) volume, which updated Safari to the 14.0.2. But it didn't run the 2020-007 - not that I had high hopes that it would. So I'm supposing that it would be necessary, as usual, to boot to my APFS formatted volume (also HDD on external), in order to run the SecUpd, which clearly SK at the HFS+ volume wasn't able to see. Looks like it basically automates (for want of a better term) and runs whatever update is available
normally. In that regard, while it was running I noticed that
softwareupdated was running, as well as the native Mac installer application - what I would expect without SK.
One of my questions in my OP was whether SK would be able to run a standalone SecUpd full installer dmg, either from the HFS+ or APFS volume? You seemed to answer that question with an overall positive, but since SK appears to depend on the Mac native update/SU processes, I don't really understand how SK would be able to begin to access a SecUpdate standalone installer dmg (or package?), which would be sitting on the Desktop.
So back to that first question, already asked at
https://forums.macrumors.com/thread...unsupported-macs-thread.2121473/post-29390944 which was, "Does this mean SilentKnight will be able to directly install a standalone SecUpd without needing to modify the distribution file,
or will it only be able to install what is already available from SU on an APFS formatted volume, as per the usual caveats?"
In other words, it's nice to have all this automated, but wonder if it actually changes anything basic to the way updates are run?