I want to know the answer to the following question:
What code eventually became neglected?
All the background I'm provided with is that "Because the keytop for the O key also showed a left-arrow symbol (from ASCII-1963, which had this character instead of underscore), a noncompliant use of code 15 (Control-O, Shift In) interpreted as "delete previous character" was also adopted by many early timesharing systems but eventually became neglected.". Is that enough to answer the question?
Answer: yes