While "source listings as an aid to debugging" was definitely done, and still is (e.g. Microsoft Windows source is available to researchers), Wikipedia disagree

While "source listings as an aid to debugging" was definitely done, and still is (e.g. Microsoft Windows source is available to researchers), Wikipedia disagrees with the use of the term "open source" as ever meaning this. The term "open source" was first proposed by a group of people in the free software movement who were critical of the political agenda and moral philosophy implied in the term "free software" https://en.wikipedia.org/wiki/Open-source_model https://en.wikipedia.org/wiki/Open-source_model