The price shown is dynamically updated to today’s dollars, and the subscript is the original value at the publishing date of the source text.

> inflation adjustment: Inflation.hs provides a Pandoc Markdown plugin which allows automatic inflation adjusting of dollar amounts, presenting the nominal amount & a current real amount, with a syntax like [$5]($1980).

except text was published in 2025

It's quoting text published before 2025.