https://en.wikipedia.org/wiki/Mexican_Americans (which is citing https://data.census.gov/table/ACSDT1Y2022.B03001?q=B03001)
In 2022, Mexican Americans made up 11.2% of the US population and 58.9% of all Hispanic Americans.
In the US, yeah, you are more likely to speak to a Mexican than any other hispanic Spanish speaker.
If you are talking about the Fennec browser (i.e. Firefox on android), this link is not pointing to that.