There are hundreds of single categories in total, so how does MC 'decide' which one to map to?
This is the issue we are dealing with. There are so many categories we can't use each category as a separate genre. Furthermore, each show gets multiple categories.
We programmatically make a map, from a category to a genre. This is a many-to-one map. In my earlier example, many categories related to "children" are mapped to the genre of "Children".
On the other hand, if a show is associated with multiple categories, we use the first one we find that we recognize. In the xmltv example you gave above, the first category we find is "Talk". Thus this show gets the genre of "Talk Show". Other categories included, such as "Newsmagazine", "News", "Interview", etc. are ignored as far as genre is concerned (if the first entry were "News", this program would get the genre of "News").
If the first category is something we do not recognize, we use the second one, or the third one, etc. An example is "Special". Sometimes a program gets "Special" as its first category. We don't make a genre of "Special" because it is too vague. Often the program also gets a category of, for example, "Nature", or "News", etc. So we use one of those, and put the show in the genre of "Educational" or "News".
Is it possible to see, in a program listing view, perhaps a custom view, the genre or genres ascribed to each program item. This would be a great help.
Yes. These "categories" are all saved in the field of "Keywords".
TV view does not show Keywords field. You can display it in one of the Video views which is more flexible. In Theater View guide, if you select a TV program and click OK/Enter button, you get a screen showing some detailed info about the show, including "Keywords". In Standard view, the guide does not show keywords and you will need to create a customized view to show them.