[ryantownsend]

iirc, most content delivery networks have now configured initcwnd to be around 40, meaning ~58kb gets sent within the TCP slow start window and therefore 14kb is no longer relevant to most commercial websites (at least with H1/H2, as you mentioned QUIC/H3 uses UDP so it's different)

[divbzero]

When and where you heard that initcwnd is typically 40 for most CDNs?

I was curious but the most recent data I could find was from 2017 when there was a mix of CDNs at initcwnd=10 and initcwnd>10:

https://www.cdnplanet.com/blog/initcwnd-settings-major-cdn-p...

Currently Linux still follows RFC6928 and defaults to initcwnd=10:

https://github.com/torvalds/linux/blob/v6.11/include/net/tcp...