MrsPernicious
Yes, it's a pre-print outlining deficiencies in some of the earlier studies on masks. It does not prove that masks are effective, it just highlights that they are not as ineffective as shown by earlier research.
ECDC has cast its net much wider and looked at every available piece of information on masks. Their conclusions are that masks are marginally helpful and we should wear them in the indoor settings but we should not overestimate their impact.
UK kids sitting mask-free at home in their bedrooms are... what? Having the time of their lives?
So are Californian kids... regardless of the universal mask mandate.
UK kids were also at school, "being inspired, communicating, creative, having fun, learning..." until we were hit by the new variant. If only masks were as effective as some people think... everything would have been so easy.
Unfortunately, masks are only a marginal mitigant and while they may help teachers and parents feel "safer", they are unlikely to make a fundamental change to the transmission dynamics.