- Improved handling of jsonpath expressions for `kubectl wait --for`. It is now possible to use simple filter expressions which match on a field's content. ([#118748](https://github.com/kubernetes/kubernetes/pull/118748), [@andreaskaris](https://github.com/andreaskaris))

- To enhance usability and developer experience, CRD validation rules now support direct use of (CEL) reserved keywords as field names in object validation expressions.

- Added authorization check support to the CEL expressions of ValidatingAdmissionPolicy via a `authorizer`

- The "value" part in the `wait --for=jsonpath='{expression}'[=value]` is now
  optional. If the value is not provided i.e., the command looks like `wait --for=jsonpath='{expression}'`
  then the wait condition is interpreted as matched when the expression returns

- To enhance usability and developer experience, CRD validation rules now support direct use of (CEL) reserved keywords as field names in object validation expressions for existing expressions in storage, will fully support runtime in next release for compatibility concern. ([#126188](https://github.com/kubernetes/kubernetes/pull/126188), [@cici37](https://github.com/cici37)) [SIG API Machinery and Testing]

- Fixed the example validation rule in godoc:
  
  When configuring a JWT authenticator:
  
  If username.expression uses 'claims.email', then 'claims.email_verified' must be used in
  username.expression or extra[*].valueExpression or claimValidationRules[*].expression.
  An example claim validation rule expression that matches the validation automatically

- When configuring a JWT authenticator:
  

- Added support for CEL expressions with escaped names in the structured authentication config. Using `[...]` to access claims or user data was recommended when names contained characters that would otherwise need escaping. CEL optionals with `?` could be used where has was not applicable...

- Fixed an error processing watch events when running skewed apiservers ([#73482](https://github.com/kubernetes/kubernetes/pull/73482), [@liggitt](https://github.com/liggitt))
- jsonpath expressions containing `[start:end:step]` slice are now evaluated correctly ([#73149](https://github.com/kubernetes/kubernetes/pull/73149), [@liggitt](https://github.com/liggitt))

## Changelog since v1.26.8

## Changes by Kind

### API Change

- Fixed a bug where CEL expressions in CRD validation rules would incorrectly compute a high estimated cost for functions that return strings, lists or maps.