Issues regarding compatibility and emulation of Rebol2 and Red.
It's generally a goal that Ren-C be able to bend in order to do most anything that they can do...with modest effort. Pursuant to that goal is the Redbol module to have an actual emulation of a reasonable compatible subset of the (non-GUI) portion of the languages.
More generally, this category is for discussing anything related to Rebol2 or Red semantics or features.
Note: R3-Alpha emulation is considered uninteresting, as it never gained much traction. Most R3-Alpha codebases are either dead, one of Oldes's projects, or have been subsumed into Ren-C projects.