I thought some CSS was cutting off the descenders, but no, it's a conscious choice. (Although it sounds from the font copy that you can get regular g's and u's by enabling an OTF alt style...?)
The g is Kagi’s logo. It made me think it’s a Kagi blog, but they’re apparently not associated, it’s just a free font called Lufga. Font was released in 2020, Kagi logo in 2021. It’s weird, Kagi branding leans quite heavily on that lowercase g. (They do, though, have the wisdom to not use it in body text.)
That is all I could think about while skimming the article.