Soft code freeze for Firefox 88 starts March 18

[Ryan VanderMeulen]

Hi all,

With Firefox 87 RC shipping soon, we are nearing the end of the Nightly 88
cycle.

In order to avoid invalidating the testing we get out of late Nightly and
to ensure that we can roll out Beta 88 to a wider audience with confidence
next week, we'd like to ask that any risky changes be avoided from Thursday
March 18 until after the version bump to 89 on March 22.

Some reminders for the soft code freeze period:

Do:
- Be ready to back out patches that cause crash spikes, new crashes, severe
regressions
- Monitor new regressions and escalate merge blockers
- Support release management by prioritizing fixing of merge blockers

Do Not:
- Land a risky patch or a large patch
- Land new features (that affect the current Nightly version) — be mindful
that code behind NIGHTLY_BUILD or RELEASE_OR_BETA ifdefs can lead to
unexpected CI results
- Flip prefs that enable new Features that were untested in the Nightly
cycle
- Plan to kick off new experiments that might impact a feature's merge
readiness

Please let us know if you have any questions/concerns.

Thanks,
Ryan

[Ryan VanderMeulen]

Hello again. The Nightly version number has been bumped to 89 and the soft
freeze is now over.

Thanks,
Ryan