What does that mean?
ABI1 is where development is done (it changes almost daily). To avoid problems there was ABI0 created, no commits there so it is stable and all software runs stable. The disadvantage it stayed the same for years. Deadwood backported all possible changes from ABI1 so there is a new improved ABI0 (faster, more reliable, better memory management and so on). Somewhen in the future there will be only ABI1 and ABI0 dropped (that will need recompilation of all software).
To show it... Aros 68k is ABI1, that meant sometimes that certain software works with one nightly and not with the next one, one is stable the other one not. I had that frequent times during the development of Aros Vision. I certainly have one or two grey hears because of this :-).
ABIs are development branches
