Most of the label global variables are considered deprecated starting from AC22.
For the complete list of them, see here.
In the meantime, lots of fix named optional parameters have been introduced to continue the role of the deprecated globals:
– label specific ones are here
– text handling related general ones (for all annotation elements) here.

So, the above is the reason why the updated GDL Reference Guide does not contain the same stuff as the previous one.
Hope this helps.