The main post of what amounts of evidence different tests give is this one: https://www.lesswrong.com/posts/cEohkb9mqbc3JwSLW/how-much-should-you-update-on-a-covid-test-result
Also related is part of this post from Zvi (specifically the section starting “Michael Mena”): https://www.lesswrong.com/posts/CoZitvxi2ru9ehypC/covid-9-9-passing-the-peak
Combining the information from the two, it seems like insofar as you care about infectivity rather than the person having dead virus RNA still in their body, the actual amount of evidence from rapid antigen tests will be higher than the amounts given in the first post. There’s a good case to be made that the sensitivity with respect to infectiousness would be 95% or more, though I am not aware of any research directly addressing this question.
You can link to specific parts of posts, and thanks to the devs, it should now also show that part in the hover preview.
Or with a hyperlink.
Use the table of contents to get the link.