This extension has become a tool for transphobia, intersexism, and exorsexism and can no longer be used to accurately determine who is transphobic and who is not. I've seen people marked green who have said some of the most transphobic stuff about other trans people, and people marked red for simply being intersex or speaking about their own experiences.
I've scrolled through the reviews recently and seen some of the developer feedback which only cements the fact that this is not a useful extension. A slur invented by cis people is still a slur no matter how it's used, and is not on par with things like "binary trans woman". And the complete lack of understanding of intersex identities with regards to "afab transfems" is just honestly disgusting. The developers of this extension are clearly trying to be the arbiters of what is and isn't allowed in the trans community and that is never a good thing.
Don't trust this extension, it's a waste of your time: you're better off vetting people the old fashioned way, which is what many people who have used the extension have had to do for years now.
This is no longer used as a tool to help the trans community but rather divide it.

Edit: a recent 5-star review: "thank god the devs are finally cracking down on transandrophobia truthers. it's time we finally kick misogynistic trans men out of the trans community for good."
These are the types of people that are abusing this extension and the types of people the dev's values are in line with. These people do not want other trans people different than them who talk about their own experiences in terms they don't like, to be in community with them. This is the type of transphobic vitriol this extension enables, and it needs to stop.
Don't use it, and instead make your own informed decisions about who you wish to block or interact with.