10 months ago ago tuned -- refining auto-update 15e9ed5b28fb;
10 months ago ago isabelle update_cartouches -t;
22 months ago ago ROOT cleanup: empty 'document_files' means there is no document;
2017-04-24 ago clarified parent session images, to avoid duplicate loading of theories;
2016-02-13 ago clarified ISABELLE_FULL_TEST vs. benchmarks: src/Benchmarks is not in ROOTS and thus not covered by "isabelle build -a" by default;