Background
I often find myself making wide header images (for websites and such) by manipulation a full-size photograph and crop the entire image as a last step. That way I can use different crops of the same source image. Often I need to perform the crop, save a jpg, upload it and see how it looks where it is supposed to be. I am usually not content so I have to undo the crop, change some color or indeed the size/location of the crop itself and do it again. This means I either have to try to do the exact same crop multiple times or I have to try to do the same crop but with just a little adjustment.

Question
Is there any way to do non-destructive cropping in Krita? I am looking for something like a crop-layer on which the crop selection can be seen and edited, and when this layer is visible, any rendered image is cropped. This needs to work when the image already has multiple layers.

I have not seen any good way of doing this in other software but it really seems that Krita should have non-destructive cropping somewhere.

No... Saving a crop should be implementable as a script, but that would be a bit of a trailblazing exercise.

There is a way to simulate a 'saveable' crop using a Local Selection Layer.

If you put your multi-layer image into a group and then clone the group, you can apply a local selection layer to the clone and make a rectangular (or any shape) selection in that clone layer's local selection layer. You can have more than one clone, each with its own local selection layer, each with a different 'crop' selection.

Then, you select the clone and the selection becomes visible. You do Edit - > Copy followed by Edit -> Paste into New Image then you can Export from the new image, which is a 'cropped' version of the cloned original image. The original image and its 'crop clones' are saved in the .kra file so you can work on them later.

That is a pretty good workaround. Thank you!