A script written for upstream that requires vnd.stalwart.expressions or vnd.stalwart.while keeps running after a move to INBUXA, since scripts are stored compiled. But it can't be saved again once edited: the old name parses as an unknown extension, and let or eval then fails with "Undeclared capability 'vnd.inbuxa.expressions'". Both spellings now parse to the same capability. Only the INBUXA names are advertised.