What does network.http.http3.sni-slicing do in Firefox?

Hi everyone,

I came across the Firefox preference network.http.http3.sni-slicing, which appears to be related to HTTP/3 and SNI handling. However, I’ve found very little documentation explaining what it actually does.

Could someone with knowledge of Firefox internals or HTTP/3 clarify:

• What exactly does this setting change in the browser’s behavior?
• Does it provide any privacy or security benefits?

I’d appreciate any insights. Thanks!