How do I change posts page header copy

WordPress 5.5.3
theme: 3.0.2
GP Premium: 1.12.2
Using "Agency" from the site library

On the posts page of the site I'm developing: http://jeria.sg-host.com/nonprofit-blog/

The default copy is "Our latest articles." at the top. If I change the posts page, this copy is displayed at the top of any page I make the posts page.

How do I change the text, "our latest articles"? I couldn't find it in the CSS.

Thanks,

Jen