Similar oneliner to paste on MacOS terminal and get the eldest line for each file extension:
for ext in $(git ls-files | grep -vE 'node_modules|\.git' | awk -F. '{if (NF>1) print $NF}' | sort -u); do echo -e "\n.$ext:"; git ls-files | grep "\.$ext$" | xargs -I {} git blame -w {} 2>/dev/null | LC_ALL=C sort -t'(' -k2 | head -n1; done