What time period and area did you come across this usage? As I ever saw it used, 'reverse engineering' generally referred to creating docs from executables or watching network protocols rather than from source.
Back in the 1990's. As an example, back then the Rational Rose design software had a feature to generate UML diagrams from existing source code, and it was called "reverse engineering".
https://en.wikipedia.org/wiki/IBM_Rational_Rose