afford more parallelism for sessions (instead of theories in 5eac4b13d1f1): depend on disjoint data areas (notably base.session_theories in 2ad892ac749a);
syntax: glob
*~
*.class
*.jar
*.marks
*.orig
*.rej
.DS_Store
.swp
syntax: regexp
^contrib
^heaps/
^browser_info/
^doc/.*\.pdf
^src/Tools/VSCode/out/
^src/Tools/VSCode/extension/node_modules/
^Admin/jenkins/ci-extras/target/