The closest thing I have is Ghostery, which is just an inspector. I don't use any extensions to modify the code of a page, so yeah I'm not sure either. I also use Firefox, just checked this at work and I'm seeing the same results. And the dev tools here agree with your findings -- both normal and text are using the same font. The only thing I can think of is that the font itself (on my Linux computers) have a different "A" for the two styles. Ah well, not something I care enough to dig in to further, I just thought it was odd to see that discrepancy.