Nightly-only:

• layout.css.round.enabled,
• layout.css.mod-rem.enabled
• layout.css.nan-inf.enabled
• layout.css.exp.enabled
• layout.css.abs-sign.enabled

With recent NaN/inf improvements, we pass 100% of WPTs for many of these now, opened a few sub-bugs for some to try and get them shipped :)
(it is probably better to do many individual bugs(/intents?), even though it is a bit messy/spammy since they are separate prefs?)

Merged individual bugs for each back into this for one patch (and intent to ship) to enable all.

Specifically enabling these prefs (previously nightly only):

• layout.css.round.enabled
• layout.css.mod-rem.enabled
• layout.css.exp.enabled
• layout.css.abs-sign.enabled

Release Note Request (optional, but appreciated)
[Why is this notable]: 10 new CSS math functions enabled by default
[Affects Firefox for Android]: Yes
[Suggested wording]: 10 new CSS math functions are now supported: round, mod, rem, pow, sqrt, hypot, log, exp, abs, sign.
[Links (documentation, blog post, etc)]: MDN articles exist for most of these functions, eg abs()

https://hg.mozilla.org/mozilla-central/rev/d84e836e4765

Intent to ship: https://groups.google.com/a/mozilla.org/g/dev-platform/c/NIPFVkhGR6I

Added to our 118 Nightly release notes, thanks.

MDN & BCD changes can be tracked in the following GitHub issue: https://github.com/mdn/content/issues/28840