Admin/init
2021-05-17 kleing avoid unexpected output+behaviour when CDPATH is set
2021-05-07 wenzelm proper "$?";
2021-04-17 wenzelm clarified options (again);
2021-04-17 wenzelm more options: update ISABELLE_IDENTIFIER;
2021-04-16 wenzelm clarified options;
2021-03-31 wenzelm clarified (again): local tip could be actually more recent;
2021-03-31 wenzelm tuned;
2021-03-31 wenzelm clarified name;
less more (0) tip