I had to look up what KDL is and what `Functional Source License, Version 1.1, ALv2 Future License` is.
So KDL is like another JSON or Yaml. FSL-1.1-ALv2 is an, almost but not really, open source license that after a 2 years becomes available under a real open source license. It's to prevent free loading from companies or something. Sounds fine to me actually.
Effectively, it's not meant to restrict people from using it, even in a commercial setting, just to protect my personal interests in what I want to do with it in a commercial setting.
KDL is more than just JSON or YAML. It's node based. It's output in libraries is effectively an AST and its use cases are open ended.
For me the acronym clash was "DSL". Presumably a language for sucking information off web pages.
Domain Specific Language - It's a fairly common acronym I feel like. SQL is a DSL, so is CSS, Rust macros lets you create DSLs, for example. The opposite is General Purpose, like Python, JavaScript