JASP Bayesian ANCOVA Model Averaged R2
I am struggling a little bit to get some information on the meaning of the "Model Averaged R2" output in a Bayesian ANCOVA (JASP 0.11.1).
The short context is that a reviewer *really really* wants to see R2 and 95% CIs from a frequentist ANCOVA to understand how much extra variance the variables in the winning model (in the bayesian approach) explain over the null or the model without those key variables the BF of the model over the null or the model with all the "other" variables was apparently not persuading despite them being very large in terms of weight of evidence..).
My first thought was to reverse-infer the R2 from the BF, but I guess I can only get a proportionality relation between the two (i.e., I can calculate BF from 2 R2, but cannot go the other direction -- right?). So next, I found the "Model Averaged R2" option, but I'm not sure I fully understand it. Is that the "non-frequentist" R2 (i.e., the R2 considering all the models, not just the point-estimate of the best model a la frequentist R2?)
I ask because unfortunately there is very little on the bayesian ANCOVA -- I spent quite some time on google but with no luck, and the Bayesian ANCOVA has no entry in the https://jasp-stats.org/how-to-use-jasp/