Hi All,
I finally got around to installing the Catalina 10.15.3 update (Build 19D76) on my Desktop and Laptop Hacks.

I downloaded the update from the link in the first post as i have multiple machines to update. This was a quick and slick update which took around 10 mins on each machine with the usual three reboots.
Prior to installing I did not update Clover (currently running r5100) and I left all 3rd party kexts installed in /Library/Extensions, I only have Lilu + VirtualSMC in /EFI/Clover/Kexts/Other which is the bare minimum required to run the Updater / Installer / Recovery processes ("Inject kexts" set to "detect" in config.plist)
Both machines are running perfect after the update ( just like they where before the update) so Apple have not changed anything with regards to kext certification or if they have it does not have an effect when booting with SIP partially disabled with CSRActiveConfig set to 67 in the RTVariables section of the config.plist.
As I always do after installing a MacOS update, I rebuilt the kext cache using Hackintool and re-run PikeAlpha's FrequencyVectors shell script to ensure all CPU clock states where re-enabled.
One observation I've seen on my my desktop machine (See White Knight build in my sig) is that 10.15.3 has reduced the BruceX 5K export in FCPX from 12.3 seconds to 8.2 seconds. This was unexpected as i did not think there was much in this update that would effect Hackintosh systems, nice to finally get down to a sub 10 second export time with that test

.
Since I have not updated FCPX in while i can only assume that 10.15.3 includes some optimisations to the Metal 2 and/or VideoToolBox API's or possibly the AMD Vega drivers. Other than that not much else to report.
Cheers
Jay