How to download Xcode header files for Mac OS Catalina?

I'm using Mac OS 10.15.4 Catalina.

macOS Mojave had a known issue whereby users need to download missing Xcode headers.

I have no headers in /usr/include

Multiple StackExchange questions and blogposts addressed this question, by recommending users do (roughly) the following:

#run installer via command line sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target / 

• https://silvae86.github.io/2018/07/05/fixing-missing-headers-for-homebrew-in-mac-osx-mojave/

• https://donatstudios.com/MojaveMissingHeaderFiles

However, I cannot find /Library/Developer/CommandLineTools/Packages/.

I tried removing the command line tools and re-installing as follows:

$ (sudo) rm -rf /Library/Developer/CommandLineTools $ xcode-select --install 

However, I still don't see:

/Library/Developer/CommandLineTools/Packages/ 

How are these header files made available for Catalina users?