Firefox Money: Investigating the bizarre finances of Mozilla (lunduke.substack.com)

"Paywall" might not apply. "Premium" is the term in play at an otherwise "freemium" website.

The question really is: how do you want to pay for your free lunch?

Substack is one of many such "freemium" infrastructures; authors can gain some level of remuneration for their work by publishing general information in the free zone, but adding deeper analysis in the premium zone.