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Necko Team – Weekly Status Meeting Notes

Date: 2026-03-03
Edition: March
Facilitator: Greg
Next on Triage: Valentin Gosu
Quality Report Coordinators (March): Valentin Gosu / Sunil Mayya

Round Table

Andrew Transitioning to Collaboration Role

  • Andrew is rolling off as a full-time Necko team member after ~4 years 🎉

  • Moving to a collaboration model between Networking and Performance.

  • Will join meetings for agreed joint projects (e.g., Speculation Rules / Prefetch).

  • Will no longer attend recurring Necko meetings by default.

  • Remains reachable in #necko and #perf-help.

  • Team thanked Andrew for his contributions and ongoing partnership.

Gecko Code Review AI Feedback

  • Positive experience using AI tooling for code review.

  • Identified improvements such as:

    • Cycle collection gaps

    • Spec-step documentation

    • Raw pointer safety notes

  • WebTransport exportKeyingMaterial() implementation approved:

    • Spec compliant

    • Secure

    • Thread-safe

    • Well-tested

    • Clean cross-layer integration

  • Reinforced value of AI-assisted review for complex networking code.

RCWN (Race Cache With Network) Disablement

  • Feature considered technical debt (two code paths).

  • Previous experiment showed negligible impact.

  • HDD usage now <7% on Windows.

  • Decision:

    • Disable RCWN.

    • File tracking bug and prioritize in queue.

    • Focus engineering effort on cache improvements instead.

  • Action: File meta bug to disable and eventually remove RCWN code.

Cross-Team Coordination (DevTools)

  • Proposal from DevTools to increase cross-team connectivity.

  • Decision:

    • Not add to weekly status.

    • Explore quarterly/bi-yearly sync for roadmap alignment.

    • Use Slack for ad-hoc coordination.

  • Water cooler remains informal; no structural changes.

Team Check-ins (Highlights)

  • Lars

    • PR_POLL implementation progressing.

    • Performance testing positive on Linux/macOS.

    • Windows historical fix landed.

  • Kershaw

    • Landed first Happy Eyeballs version.

    • Investigating CrowdStrike / HTTP3 fallback logic.

    • Continuing Happy Eyeballs work.

  • Valentin

    • Fixed Necko meeting notes GitHub automation.

    • Landed Sunil’s LNA patches.

    • Working on LNA:

      • Block local network requests from insecure contexts.

      • Avoid prompts when certificate mismatches.

    • Fixed intermittent cookie deletion issue (Windows pref-related).

  • Max

    • Fixed long-standing neqo issue.

    • Security fix in QPAC (with Claude assistance).

    • Investigating 10% zero-RTT rejection rate.

    • Continuing Happy Eyeballs Rust reviews.

  • Oskar

    • Continuing Hystart++ integration.

    • Addressing review comments before landing.

Important Business

Priority Queue

(Security-sensitive bugs excluded)

Bug ID

Severity

Summary

Priority

Owner

Status

2000423

S3

FormData parser non-compliant (preamble)

P2

—

—

1974877

S3

WPT failures in /cookies/samesite

P2

—

—

1965087

S3

Cookie initialization on session restore

P2

edgul

—

1962316

S3

Android VPN + network bearer change incomplete requests

P2

—

—

1732512

S3

Fetch blocked by form submit

P2

smayya

—

1962817

S3

kameleoon.js deprioritization slows render

P2

acreskey

Follow-up experiments launched

1963079

N/A

Exclude spurious document loads from telemetry

P2

—

—

2005275

S3

NS_IsMainThread assert

P2

—

—

2013783

S3

Website keeps reloading

P2

valentin.gosu

WPT added; fix in progress

2014160

S3

Cache2 I/O thread 100% CPU

P2

jesup

—

2015482

N/A

BigQuery alerting

P2

—

—

2017712

S3

LNA prompts more eager than Chrome

P2

valentin.gosu

In progress

1896460

S3

Improve Blink sniffing compat

P3

kershaw

WIP

Queue status: 23 total (12 assigned, 11 ready).

Closed Fixed (Last Week – Non-Security)

  • 1869403 – Slow system proxy page load

Active Projects

FEISTY

  • Downloads GCP migration complete and in review.

  • Downloads now unblocked.

DoH Enablement – Fenix

Early Nightly experiment data (March 2):

Pageload Event (TRR vs Native):

  • p50: +18ms (+257%) slower (early data)

  • p75: +16ms (+38%)

  • p95: +33ms (+18%)

All DNS Requests:

  • p50: +11.7ms (+41%)

  • p95: +39ms (+19%)

Cold Applink DNS:

  • p75: +74ms (+617%)

  • p95: +346ms (+449%)

Time to Request Start:

  • p50: +191ms (+43%)

  • p75: +273ms (+19%)

Notes:

  • Early data; query recently updated.

  • Reduced HTTP/3 negotiation rate under TRR.

  • Greg: Happy Eyeballs expected to improve H3 negotiation.

Local Network Access (LNA)

  • 147: 100% ETP Strict via Nimbus.

  • 148: Default enabled for ETP Strict.

  • Android Nightly enablement pending review.

  • Sunil patches uplifted by Valentin.

  • New patch: block LNA requests from insecure contexts.

  • Fix in progress to suppress prompts when cert mismatch detected.

Happy Eyeballs

  • IPv4/IPv6 preference patch in review.

  • Rust/C++ integration ongoing.

  • ABI review required before first landing.

  • FFI review requested.

QUIC / Hystart++

  • Slow start rearchitecture under review.

  • Integration work continuing.

Performance Highlights

  • Fenix Applink ~12% faster YTD.

  • Tracker tailing experiment:

    • Disabling tailing regressed FCP/LCP ~10% @ P50.

    • Follow-up experiments launched (Nightly + Beta).

  • 10% zero-RTT rejection rate under investigation.

    • Possible cookie ticket or server behavior.

    • Randell to lead investigation.

Maintenance Effectiveness:

  • Last week: 66.67% ⚠️

  • Last month: 91.92%

  • 3-month trend: 98.7%

WebCompat

Needs attention:

  • [2012345

    ](https://bugzilla.mozilla.org/show_bug.cgi?id=2012345)

  • 2017305 (possible regressor)

  • [2016092

    ](https://bugzilla.mozilla.org/show_bug.cgi?id=2016092)

Reminder:

  • Hide PII logs.

  • File new component bugs rather than reassigning WebCompat bugs directly.

Decisions & Alignment

  • Disable RCWN and remove code.

  • Maintain informal DevTools coordination model.

  • Continue DoH Nightly experiment; analyze cold applink data.

  • Investigate zero-RTT rejection anomaly.

  • Keep PQ hygiene; tag good-first-bugs during triage.

Action Items

  • Valentin

    • File RCWN disablement bug.

    • Coordinate QR during Sunil PTO.

    • Prepare monthly meeting slides.

    • Continue LNA fixes and uplifts.

  • Greg

    • Seed meeting templates before PTO.

    • Coordinate Feisty downloads fallback.

    • Explore structured DevTools sync.

  • Max

    • Continue Happy Eyeballs Rust reviews.

    • Investigate zero-RTT rejection rate.

  • Kershaw

    • Facilitate Mar 12 meeting.

    • Continue Happy Eyeballs work.

  • Team

    • Investigate new WebCompat items.

    • Reduce NI counts (<3).

    • Complete retro actions.