[umutisik]

It's called Acoustic Echo Cancellation. An implementation is included in WebRTC included in Chrome. A FIR filter (1D convolution) is applied to what the browser knows is coming out of the speakers; and this filter is continually optimized to to cancel out as much as possible of what's coming into the microphone (this is a first approximation, the actual algorithm is more involved).

[Sponge5]

To spare a search: https://webrtc.googlesource.com/src/+/refs/heads/main/module...

[sojuz151]

Remember that convolution is multiplication in the frequency domain, so this also handles different responses at different frequencies, not just delays