Highlight that 'intro_locales' and 'trace_locales' are useful debug features, plus minor clarifications.
#hard-wired components
src/Tools/jEdit
src/Tools/Graphview
src/Tools/VSCode
src/HOL/Mirabelle
src/HOL/Mutabelle
src/HOL/Library/Sum_of_Squares
src/HOL/SPARK
src/HOL/Tools
src/HOL/Tools/ATP
src/HOL/TPTP