References to Hull (Topics in Brackets)

The Official reading of this subject refers to the Core-reading, but in the Acted notes for example Chapter 9 of the Acted notes suggests that the staff on Chooser Options and Barrier Options e.tc is Optional as they are shown with brackets. And Optional is explained to mean that they are not listed explicitly in the Official reading while they are shown in the Core reading row at the bottom of page 2. This sounds like a contradiction?

Someone please explain to me what ''listed explicitly in the Official reading'' means?

 

Being ''listed explicitly in the Official reading'' refers to the reading, not the topics. So for example, although Chooser and Barrier options are required topics to know about, there is separate (non-textbook) Core Reading on these that must be read. By contrast, Hull goes into more detail and looking into this material is stated as optional, ie we think it might be useful, but it's not essential according to the profession.