How can I reduce the size of the package in Arduino15 for Arduino Uno only?

[comseong]

I want to release this arduino-cli for offline users using Arduino Uno hardware.
So I was trying to make the arduino-cli be embedding the ardunio:avr platform in the core from the first. 
By the help of issue(https://github.com/arduino/arduino-cli/issues/1190), I achieved first step.

But, the size of the package in the Arduino15 directory which is created by the command arduino-cli core install arduino:avr is almost 270MB. It's too big for the my custom release. How can I reduce the release size for Arduiono Uno only? Thanks.

[pert]

Hi @comseong! Here is what you need to keep. You can delete everything else:

• Arduino15/packages/arduino/hardware/avr/1.8.3/boards.txt
• Arduino15/packages/arduino/hardware/avr/1.8.3/installed.json
• Arduino15/packages/arduino/hardware/avr/1.8.3/platform.txt
• Arduino15/packages/arduino/hardware/avr/1.8.3/programmers.txt
• Arduino15/packages/arduino/hardware/avr/1.8.3/bootloaders/optiboot
• Arduino15/packages/arduino/hardware/avr/1.8.3/cores
• Arduino15/packages/arduino/hardware/avr/1.8.3/libraries
• Arduino15/packages/arduino/hardware/avr/1.8.3/variants/standard
• Arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17
• Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino7

Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino7 is the biggest by far. This contains support for every AVR microcontroller, but you only need the ATmega328P support for the Uno, so it's likely you could remove some files. I don't know exactly what though. I'm sure one of the other forum members will be able to provide assistance with that.