The documentation explains the use of the bands and cites the sources you want:
Comparable Model Zones
Although a model is estimated to be the best model, there can be uncertainty relative to this selection. Competing models might fit nearly as well and can contain useful information. For the AICc, BIC, KFold, and Leave-One-Out validation methods, and for a Validation Column with more than three values, the Validation Plot provides zones that identify competing models that might deserve consideration. Models that fall outside the zones are not recommended. See Burnham and Anderson (2004) and Burnham et al. (2011).
These criteria are not intended for inference. The information criteria are to be minimized, but like any metric, you should carefully examine the results and verify their validity, and not use them exclusively or blindly.
Please see the documentation for the Solution Path Plot and the associated references.