After adding https://raw.githubusercontent.com/spark ... index.json to the preferences in the Arduino IDE (1.8.13) and installing the Sparkfun AVR boards, I get below errors when I go back into the boards manager
Index error: could not find referenced tool name=xtensa-esp32-elf-gcc version=1.22.0-80-g6c4433a-5.2.0 packager=esp32 Index error: could not find referenced tool name=esptool_py version=2.6.1 packager=esp32 Index error: could not find referenced tool name=mkspiffs version=0.2.3 packager=esp32
I've seen that it's in the json so will probably be able to hack it but I would suggest that Sparkfun creates different packages for different architectures.
Observed it the first time in a normal install of IDE 1.8.5 but could not pin it at that stage. Observed it now while setting up IDE 1.8.13 in portable mode and adding the Sparkfun AVR boards.