[erkl]

QUIC operates on top of UDP, which would make it layer 5.

[paulddraper]

QUIC is the transport layer (layer 4).

> QUIC is an experimental transport layer network protocol [1]

You can run layer 4 on top of layer 4. (Just as you could say, run TCP layer 4 on top of HTTP layer 7.)

[1] https://en.wikipedia.org/wiki/QUIC