Here ya go. https://support.mozilla.org/en-US/kb/firefox-mac-osx-users-esr

I'm currently looking at a used laptops right now and eBay has a lot to chose from. Also, has deep selection of Macs.

Hi, jonzn4SUSE--

Thanks for the link. That page explained clearly that I need Firefox version 78.15.0esr; however, I have not yet been able to figure out how to download that particular version. The links from that page that I have followed so far have all ended with a download of version 91...

I just entered my question into the Support page and a Solved similar question came up. The answer is https://ftp.mozilla.org/pub/firefox/releases/78.15.0esr/mac/en-US/.

The article seemed adamant that playing with old operating systems and browsers can be dangerous. This probably suggests why eBay has a lot of old machines. I plan to use my old, 2009, MacBook Pro solely to read the news, so I think I'll be safe enough.

Thanks again.

--Gil

P.S. I just ftp'd the .dmg, copied the FF icon to Applications, launched FF from my Applications folder, and typed in my newspaper's URL. It works! I didn't even have to type in my newspaper's account name nor password (?). "About Firefox" says it's 78.15.0esr. Hooray!

Thanks, jonzn4SUSE!

--Gil