Open Preferences in Arduino IDE

Add this in Additional Board Manager URLs:

http://drazzy.com/package_drazzy.com_index.json,https://raw.githubusercontent.com/xukangmin/TinyCore/master/avr/package/package_tinycore_index.json

Note

build.path=/Users/yuichi/Arduino/build is removed in preferences.txt

Go to boardmanager

Find and install megaTinyCore 2.2.0

Select the board setting

Open Example Sketch

Verify/Compile it

Error

fork/exec /Users/yuichi/Library/Arduino15/packages/megaTinyCore/hardware/megaavr/2.2.0/create_disassembler_listing.sh: no such file or directory
Error compiling for board ATtiny3216/1616/1606/816/806/416/406.

In Terminal

% ls /Users/yuichi/Library/Arduino15/packages/megaTinyCore/hardware/megaavr/2.2.0/
create_disassembler_listing.sh
tools
% open /Users/yuichi/Library/Arduino15/packages/megaTinyCore/hardware/megaavr/2.2.0/create_disassembler_listing.sh

Install megaTinyCore2.2 Download the Python3 package - MacOS: https://github.com/earlephilhower/esp-quick-toolchain/releases/download/2.5.0-4/python3-macosx-portable.tar.gz

In Terminal

% open /Users/yuichi/Library/Arduino15/packages/megaTinyCore/hardware/megaavr/2.2.0/tools
% cd Downloads
% ls
python3-macosx-portable.tar.gz

% cp python3-macosx-portable.tar.gz /Users/yuichi/Library/Arduino15/packages/megaTinyCore/hardware/megaavr/2.2.0/tools
% cd /Users/yuichi/Library/Arduino15/packages/megaTinyCore/hardware/megaavr/2.2.0/tools
% ls
ManualPython.md         prog.py
libs                python3-macosx-portable.tar.gz

Extract

% which tar
/usr/bin/tar

% tar zxvf python3-macosx-portable.tar.gz

% ls
ManualPython.md         python3
libs                python3-macosx-portable.tar.gz
prog.py

% pwd
/Users/yuichi/Library/Arduino15/packages/megaTinyCore/hardware/megaavr/2.2.0/tools

As Manual said
The tools folder should now contain that python3 folder, a libs folder, and prog.py

REF

ref. https://github.com/SpenceKonde/megaTinyCore/blob/master/megaavr/tools/ManualPython.md
ref. https://github.com/SpenceKonde/megaTinyCore/releases/tag/2.2.1-manual