Where does “ins Einzelne gehend” come from?

ins Einzelne gehend (German) comes from German ins Einzelne gehen — to go into details, to particularize.

ins Einzelne gehend (German): detailed; detailedly

Definitions

Step	Language	Word	Meaning
1	German	ins Einzelne gehen	to go into details, to particularize

ins Einzelne gehend — Etymology, Origin & Word History | Etymology Explorer