CEL looks interesting and useful, though it isn't common nor familiar imo (not for me at least). Quoting from https://github.com/google/cel-spec
# Common Expression Language
The Common Expression Language (CEL) implements common
semantics for expression evaluation, enabling different
applications to more easily interoperate.
## Key Applications
- Security policy: organizations have complex infrastructure
and need common tooling to reason about the system as a whole
- Protocols: expressions are a useful data type and require
interoperability across programming languages and platforms.
