This one's actually interesting to me, but I wouldn't try to read too much into it. It's interesting because there's basically zero, controlled, laboratory significance(IMO) but rather it's an interesting real life look.
They ostensibly used Powecom KN95's distributed by their university, but Powecom had all sorts of problems in that era with counterfeit masks, and it was unclear whether they actually ever qualified for the FDA emergency use authorization at the time as they claimed to be covered by a surgical mask authorization.
But beyond that, in each category, they allowed people to bring in their own "unknown brand" masks for the study.
The conclusion's solid in that N95s are best. At least to me, it shows the pitfalls of random masks rather than their conclusion ranking different categories of masks in terms of efficacy. Find what has reliable manufacturing and supply chain and that fits you and stick with it.
https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(24)00192-0/fulltext
To me:
Something > Nothing
N95 > all other disposable masks
Everything else in-between is always hazy based on fit, brand, etc.
