Highlights for ESMValCore v2.12.0 release

[sloosvel]

@ESMValGroup/esmvaltool-developmentteam This discussion collects possible highlights for release v2.12.0 ⭐

Please add pull requests that you want to nominate as answers below, afterwards people can vote for their favorite new feature.

The top pull requests will be highlighted in the upcoming release!

Rules:

Exactly one PR per answer
Only already merged PRs are allowed

[malininae]

I suggest this

[bouweandela]

I would suggest the following:

• New way of configuring the tool. Implemented by @schlunma in a series of pull requests: Merge configuration object from multiple files (instead of one single file) #2448, Make Dask configurable in our configuration #2616, and the pull requests listed under 'Configuration' in the changelog (where the first two should probably be mentioned too).
• Further performance improvements, especially Add an iris-esmf-regrid based regridding scheme #2457 since it may affect regridding results for 2D grids and adds the capability to regrid UGRID meshes out of the box, but Only save data from one preprocessing task at a time with the Distributed scheduler #2610 and Use better defaults when using max_parallel_tasks with an unconfigured threaded scheduler #2626 are relevant too since they may affect how users configure the tool.
• On-the-fly cmoriser for ACCESS native data (Pull request #2430)

[bouweandela]

By the way, I noticed that the upgrade guides we usually have for deprecated and backward incompatible changes are still missing from the changelog too. Don't forget to bug the authors of those pull requests about adding them (that would be @schlunma and me..)