Someone wrote an RSS reader in COBOL, which just blows my mind.
Also, I didn't know this since I've only ever touched COBOL on mainframes without the licensed bits from SPC Systems that would otherwise include the precompiler for it, but the ANSI standard apparently has a report writer facility, and GnuCOBOL supports it. That's the bit that you see drawing the user interface shown in the screenshots in the README for that repository.
(Apropos the report writer bits on mainframes, it's common that you're running your code under the auspices of an interactive transaction monitor like CICS, where you're using BMS^Wassembly language macros to define panels to show on the terminal and writing a configuration file to wire it all up. In the batch case, the job entry system handles the reporting details for you, provided that you write your JCL the right way. It could wind up coming out of a line printer or being held on the spool.
On OS/390 and modern z/OS, you even get a facility called Advanced Function Presentation (AFP), which allows you to create pretty forms that you can then overlay with data that's output from a job for bulk printing things like bills. You've almost certainly gotten something in the mail that was printed this way.)
This all said, COBOL is definitely not the first thing that comes to mind for an application like this. It's a domain-specific language for writing line of business software, which is a class to which this RSS reader absolutely does not belong.
If I were to go about this in a language commonly associated with mainframes, I'd probably lean on PL/I, but I digress.