Starting in macOS 10.15, the Quartz Composer framework is deprecated and remains present for compatibility purposes. Transition to frameworks such as Core Image, SceneKit, or Metal. (50911608)
Tragic but unsurprising. None of those are even remotely a replacement, being machine-level programming tools, not a graphical tool for assembling a graphics or sound workflow. But there's probably almost nobody using QC anymore, because Apple neglects it and won't promote any dev tools except horrible goddamned walking abomination Xcode.
Script Editor might quit unexpectedly when saving or executing scripts. (50470730)
Scripting Language Runtimes
Scripting language runtimes such as Python, Ruby, and Perl are included in macOS for compatibility with legacy software. Future versions of macOS won’t include scripting language runtimes by default, and might require you to install additional packages. If your software depends on scripting languages, it’s recommended that you bundle the runtime within the app. (49764202)
Use of Python 2.7 isn’t recommended as this version is included in macOS for compatibility with legacy software. Future versions of macOS won’t include Python 2.7. Instead, it’s recommended that you run python3 from within Terminal. (51097165)
More of the same, increasingly neglected non-Xcode tools.
Killing python2 is great. It's not clear if python3 will be included standard, or if you have to find that somewhere else.
On my old blog, I had a post "Macs Make Programmers", where I talked about all the great scripting languages and tools included in OS X, including Xcode back when it wasn't broken junk. Timmy Cook's Apple is making that very difficult.
So basically the first thing you need to do on a Mac is install MacPorts,
sudo port install python3 and so on.
On the bright side:
This is a massive step up in security and usability. I was a long-time ksh user on HP-UX, Atari ST MiNT, and OS/2, switched to bash for Linux back in '95-ish, and went along with bash on OS X, even though the original default was tcsh. I switched to zsh in 2014, after the bash shellshock bug; and it was long overdue. Apple can't follow the current bash versions because they're under poisonous GPLv3, so even with shellshock patched it's still not safe. zsh is reasonably current and MIT-licensed so it can stay current.
You want one reason to switch right now?
In bash, that removes two files, "foo" and "bar". In zsh, it removes one file, "foo bar" (you can get the Bash-like behavior of expanding args by
rm $(echo $F), probably some other ways).