This link is for PDF-aware developer tools:
Specifically, the 1.7 reference that DarkLighting mentions is:
Section 3.2.4 of the document seems to address your question:
A name object is an atomic symbol uniquely defined by a sequence of characters.
Uniquely defined means that any two name objects made up of the same sequence of characters
are identically the same object. Atomic means that a name has no internal structure;
although it is defined by a sequence of characters, those characters are not considered
elements of the name.
A slash character (/) introduces a name. The slash is not part of the name but is
a prefix indicating that the following sequence of characters constitutes a name.
There can be no white-space characters between the slash and the first character in
the name. The name may include any regular characters, but not delimiter or white-space
characters (see Section 3.1, “Lexical Conventions”). Uppercase and lowercase letters are
considered distinct: /A and /a are different names. The following examples are valid
/1 . 2
So it would seem that /JT /Cn /V and so-on are named objects within a PDF Dictionary Object (identified by double angled brackets << ... >>). In your examples, all of these "unidentified" elements are contained within dictionary objects. See section 3.2.6 for a more detailed description of this element.
It's also conceivable that these are part of the PDF extensibility options described in 2.2.8:
Additionally, PDF provides means for applications to store their own private
information in a PDF file. This information can be recovered when the file is
imported by the same application, but it is ignored by other applications.
Therefore, PDF can serve as an application’s native file format while its
documents can be viewed and printed by other applications. Application-specific
data can be stored either as marked content annotating the graphics objects in
a PDF content stream or as entirely separate objects unconnected with the PDF content.
Basically, it's hard to tell what all the various non-standard objects are defined as without going through each one and decoding it (either through a self-developed automation tool or manually).
I non-concur with DarkLighting regarding the /GoTo comment. PDF renderers should read the entire contents of the dictionary before taking any action. The PDF specification does not state that order is important - only that both the "/S /GoTo" and "/D <[some kinda destination]>" are declared. In your example it says go to Page 9, Location 0.