I have good news for ATAPI / PATA internal CD player users on MP3,1.
I have MacOS Standard HFS discs mounting properly on Catalina Beta 3.
Here's what you need and don't need.
Catalina Beta 2 has the missing PATA kext inside the IOATAFamily.kext, so you don't need Mojave's and the other Kext's in this set are the same version as Beta 3. You can use the entire IOATAFamily.next from B2.
Next, The HFS and HFSEncodings seem to be foobarred in Beta 3, they will see the Mac OS Standard HFS CD volume, but they will not mount, burn, copy to a dmg or anything. You will get nothing but errors. You may even get kernel panics or Finder relaunches when trying to burn something.
So, from Mojave using the HFS and HFSEncodings.kext's and you'll be back in business with legacy HFS CDs. I do not know what the changes are in the newer HFS Kexts, but my assumption is Apple dropped support for HFS and kept HFS+ in. If they did that shame on them because Apple has kept support for Windows, MBR, NTFS, ExFat, Fat32, DOS, etc. So why on Earth drop one of your native disc formats even if it's old and keep all the PC ones?
I will be updating my CatWoman patch shortly that includes ATAPI/PATA/ATA/HFS Support. If you get operation not permitted, you can ignore the errors, the kexts copy over fine. Could be the system trying to set itself back to read only while in flight, even though the disk is set to read write before the operation starts.
Update: I wrote over my B3 install by mistake when I thought ASR was just replacing the Data volume and it the whole disk and did not honor the slice. Apple remove file copy from ASR. In the future, I'll use rsync or ditto to copy - Data volumes. I'll update the CatWoman patch tomorrow.