The Variable Text.
That various texts (e.g., the Lollard Pater Noster Commentary) exist in multiple forms for which the direction and motivation for changes cannot be ascertained leads one to speculate whether the usual sequential account of the versions of PPl might be, at least in part, reversible; i.e., is it impossible that A might be an abbreviation of B, and Z an alternative, more drastic truncation? Might B and C be independent modifications of a lost hyperarchetypal text?