> in the end it would appear that the only real impropriety is the numbering scheme

Both MUI4.0 and MUI4.2 are MUI4 :-)

> AND the borrowing of code.

Which code?

> why they would want [...] MUI4 compatibility

Isn't the accusation that they're making their MUI4 incompatible with MorphOS MUI4+ on purpose? :-)