The bed mesh is a probed map of the surface of the bed plate, normally automated and with a z probe, that describes how flat (not how level) the surface of the bed is above the level plane. It's a map of the hills and valleys decribing the warpage of build surface. The bed mesh variance, shown above is what we care about, as it should be less than 2x the layer height.

It's often erroneously called “ABL”, “Automatic Bed Leveling”, yet has nothing to do with the bed being level.

What should we be concerned about? The variance and the shape.

The variance is the difference between the highest spot on the plate above the level plane to the lowest spot on the plate below the level plane. It's calculated for you in Fluidd]'s Tuning page. So long as the variance above isn't much more than a layer height, and variance below isn't much more than layer height, the printer can easily compensate and likely won't cause functional or cosmetic issues. So a variance of less than 1.5 time layer height should be fine. === Shape === We bed mesh will most likely not be flat, nor do we expect it to be. Technically it can have all sorts of hills and valleys and [[Klipper will happily compensation. So for a large part the bed mesh is what it is. If it's not problematic, it's fine.

Yet it shouldn't be grossly warped if we can help it and what we can change is the amount of tension of the bed screw springs pushing up on the plate. Too much, or too uneven, tension can cause the plate to buckle. This can be fixed.

The Klipper Documentation for the bed mesh.

All3DP: Klipper: Bed Mesh – Simply Explained

It's helpful to turn on the level plane and wireframe checkboxes to better visualize the mesh.