I wanted to do the same using German sites for my EPG data.
What I did is search the Kodi and Tvheadend source codes for their EPG categories.
https://pastebin.com/nwjFgf1P
This is a part of the Tvheadend source code (
https://github.com/tvheadend/tvheadend/blob/master/src/epg.c) and shows all possible EPG categories in Tvheadend.
Using these categories with WebGrab++ will show you categories in Tvheadend, and therefore in Kodi (with different colors) aswell - even in your own language.
To gain the correct EPG categories in WG++, I had to edit the site ini (the ones you can download at http://webgrabplus.com/epg-channels).
This is an example, how I edited the German site rtv.de.ini:
index_category.modify {replace(type=regex)|"^Abenteuerserie$"|Movie / Drama}
index_category.modify {replace(type=regex)|"^Arztserie$"|Movie / Drama}
index_category.modify {replace(type=regex)|"^Drama$"|Movie / Drama}
index_category.modify {replace(type=regex)|"^Actionfilm$"|Movie / Drama}
index_category.modify {replace(type=regex)|"^Actionserie$"|Movie / Drama}
index_category.modify {replace(type=regex)|"^Serien$"|Movie / Drama}
index_category.modify {replace(type=regex)|"^Familienfilm$"|Movie / Drama}
index_category.modify {replace(type=regex)|"^Heimatfilm$"|Movie / Drama}
index_category.modify {replace(type=regex)|"^Dokumentation$"|Documentary}
index_category.modify {replace(type=regex)|"^Kochen$"|Cooking}
...
I just added those entries to the end of my file, after "actor.modify {remove(type=regex)|\s...\s.*$}".
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If anyone knows a better way on how to rename multiple categories to a proper one for use in Tvheadend, please say so :)