Returns the fitted formula design metadata stored by
JAGS_fit(). The design contains the processed formula, fitted model frame,
exact model matrix used for JAGS data construction, replayable expression
syntax and dependencies, JAGS-safe coefficient names, contrast and factor-
level metadata, rank diagnostics, prior metadata, and formula-scale
information.
JAGS_formula_design(fit, parameter = NULL)a fitted object returned by JAGS_fit().
optional formula parameter name. If NULL, all stored
formula designs are returned.
A named list of formula designs, or one formula design when
parameter is supplied. Returns NULL when no formula design
metadata is stored on fit.