Learn How to Write a Parser!
This isn't a tutorial, but a command: learn how to write a parser!
I'm a firm believer in understanding your abstractions, but that's not the most compelling reason: it's actually something you can use at work. Not all the time, but it's very handy when you do.
For example, a past client of mine had a spreadsheet of drug names that roughly followed the format:
DrugName Formulation (GenericName) Dosage
We were building custom software to replace this spreadsheet and needed the different fields enshrined in the database somehow. Using the first tokenizer I learned about in Crafting Interpreters, I wrote a tokenizer to extract those pieces of data. It looked very similar to this.
It took a few hours to handle some edge cases and some back and forth with the client to understand the true anomolies, but most of the data was there. We could import it into our new system and have the client fix the small handful that couldn't be parsed.
Building parsers, and other related skills, are useful. Is it a niche problem for most web devs? Absolutely: don't learn it before you learn CSS or a web framework. However, it's a great tool to have in your software toolbox for when the time arises.