anchor.diff:   * Add x-opaque-id to search slow logs {pull}31539[#31539] (issue: {issue}31521[#31521])
   
   Machine learning::
  -* If a {ml} datafeed is configured to use cross cluster search to retrieve data, 
  -the remote clusters must have {xpack} installed and a valid licence for {ml}. 
  -If the licence requirements are not met, datafeeds using cross cluster search 
  +* If a {ml} datafeed is configured to use cross cluster search to retrieve data,
  +the remote clusters must have {xpack} installed and a valid licence for {ml}.
  +If the licence requirements are not met, datafeeds using cross cluster search
   will not start. {pull}31247[#31247]
    * Use default request durability for .ml-state index {pull}32233[#32233]
    * Return statistics about forecasts as part of the job stats and usage API {pull}31647[#31647] (issue: {issue}31395[#31395])
  
positive.code: * Reduces the memory consumed by distribution models ({ml-pull}162[#162], {ml-pull}146[#146])
  * Forecasting of large machine learning jobs is now supported by temporarily storing
  model state on disk ({ml-pull}89[#89])
  * Secures the machine learning processes by preventing system calls such as fork 
  and exec. The Linux implementation uses Seccomp BPF (secure computing with 
  Berkeley Packet Filters) to intercept system calls and is available in kernels 
  since 3.5. On Windows, Job Objects prevent new processes being created and macOS 
  uses the sandbox functionality ({ml-pull}106[#106], {ml-pull}98[#98])
  * Fixes a bug that caused underestimation of the memory used by shared pointers. 
  Also reduces the memory consumed by unnecessary reference counting ({ml-pull}121[#121], {ml-pull}108, {ml-pull}115[#115])
  * Reduces model memory by storing the state for testing predictive calendar 
  features in a compressed format ({ml-pull}137[#137], {ml-pull}127[#127])
  * Always combine duplicate samples when updating population models ({ml-pull}74[#74])
  * Speeds up trend model component prediction ({ml-pull}73[#73])
  
negative.code:  * Rollups no longer allow patterns that match its `rollup_index`, which can lead to strange errors. {pull}30491[#30491]
   * A new API allows getting the rollup capabilities of specific rollup indices,
   rather than by the target pattern. {pull}30401[#30401]
   * Validation errors thrown while creating a rollup job are now a specialization of the previous `ActionRequestValidationException`, which makes it easier to catch.
   The new exception is `RollupActionRequestValidationException`. {pull}30339[#30339]
   * Validate timezone in range queries to ensure they match the selected job when
   searching. {pull}30338[#30338]
  