The datasheets in question are from parts like 555 and logic, parts that are functionally generic. No one has a doubt about how it works, but details like timmi

The datasheets in question are from parts like 555 and logic, parts that are functionally generic. No one has a doubt about how it works, but details like timmings specification and other small print parameters have had a lot of changes, because the design has been ported along each time the manufacturing process has changed. It’s cases like the one you mention when you want to know that the new parts have different parameters and you might need to change other components to compensate.