What font does Firefox use for Helvetica?
Firefox's Reader View seems to me to show a font that is similar to Helvetica. If I try to make it use only Inter, Arial, or "sans-serif", then it changes the font. What font is Firefox using instead? This also happens in Firefox forks.
If you happen to be on Linux, then it's likely one of these: https://askubuntu.com/a/1148258
Seems to be Nimbus Sans, thanks for the link!
Could it be "Fira Sans"?
https://mozilla.github.io/Fira/
The T has overhangs, and putting the Fira font page into reader view changes the font.