more robust parser: 'imports' are mandatory except for bootstrapping Pure;
more robust parser: 'imports' are mandatory except for bootstrapping Pure;

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle