It uses Ofront+ -- a descendant of Ofront. So that's another transpiler. Ofront+ is much more developed, for example it allows compiling in Oberon-07 standard

It uses Ofront+ -- a descendant of Ofront. So that's another transpiler. Ofront+ is much more developed, for example it allows compiling in Oberon-07 standard with the addition POINTER TO ARRAY and 2-byte CHARs. That is what Free Oberon uses by default. In future versions of Free Oberon, there will be a selection of Oberon standards (Ofront+ provides Oberon 1990, Oberon-2, Oberon-07, Component Pascal, and the so called Oberon-3).