Yes it has improved, mostly thanks to Cloudflare network. From my machine (gigabit fiber), for
git clone https://github.com/torvalds/linux --depth=1 --no-checkout
a warmed clone through gitdelivr.net took ~5s versus ~18 directly from GitHub (Github seems to cap clones at around 30 MB/s or 250 mbit/s) so about 3x faster in that case.