Wikivoyage:
https://en.wikivoyge.org/wiki/Wikimania_2018_Cape_Town_Guidebook
has a page with advice for Wikimania attendees. It's a good start, but needs more local knowledge. Please help to improve the page if you can
For instance, South Africa uses both "Europlug" and "type D" power sockets - but which is most prevalent at the city's hotels, and the conference venue?