Security review requested for CSS Conditional 3

Hi there,

CSS Working Group requests Security review of CSS Conditional 3
https://drafts.csswg.org/css-conditional-3/

This module contains the features of CSS for conditional processing of
parts of style sheets, conditioned on capabilities of the processor or the
document the style sheet is being applied to.
The main extensions compared to CSS level 2 are allowing nesting of
certain at-rules inside@media  <https://drafts.csswg.org/css-conditional-3/#at-ruledef-media>, and the addition of the@supports  <https://drafts.csswg.org/css-conditional-3/#at-ruledef-supports>  rule for
conditional processing.

There is a Privacy and Security Considerations section
https://drafts.csswg.org/css-conditional-3/#priv-sec

Answers to the Self-Review Questionnaire: Security and Privacy are at
https://github.com/w3c/csswg-drafts/issues/5567

We would prefer responses and discussion to also happen on that issue,
but please feel free to open other issues on that GitHub for any
substantive issues discovered.

The specification has been at CR since 2013
https://www.w3.org/TR/css3-conditional/
https://lists.w3.org/Archives/Member/chairs/2013JanMar/0130.html
but due to the long interval since that time,
CSSWG is restarting wide review before publishing a
Candidate Recommendation Snapshot.

There is a list of changes since the 2013 CR
https://drafts.csswg.org/css-conditional-3/#changes

The specification is widely implemented
https://test.csswg.org/harness/results/css-conditional-3_dev/grouped/
and we expect to meet the CR exit requirements in the next few months.

-- 
Chris Lilley
@svgeesus
Technical Director @ W3C
W3C Strategy Team, Core Web Design
W3C Architecture & Technology Team, Core Web & Media