I personally like XML a lot for rich text (I like HTML better than TeX) and layout (like in JSX for React), and it's not horrible if you want a readable represe

I personally like XML a lot for rich text (I like HTML better than TeX) and layout (like in JSX for React), and it's not horrible if you want a readable representation for a tree, but I can't imagine using it for any other purpose. JSON is exactly designed for object serialization. XML can be used for that purpose but it's awkward and requires a lot of unnecessary decisions (what becomes a tag? what becomes an attribute? how do you represent null separately from the empty string?) which just have an easy answer in JSON. And I can't think of any advantage XML has to make up for that flaw. Sure, XML can have schemas, but so can JSON. I will agree that JSON is horrible for config files for humans to edit, but XML is quite possibly even worse at that. I don't really like YAML, either. TOML isn't bad, but I actually rather like JSON5 for config files - it's very readable for everyone who can read JSON, and fixes all the design decisions making it hard for humans to read and edit.