Can you go to a Conference in Canada on a Visitor Visa, or only a Business one?

As far as I can tell from the Visit Canada official website section on visas, there are three main kinds approvals for non-Canadians making a short trip: eTA (for visa-waiver nationals coming by air), Visitor Visas and Business Visas

For someone who isn't from a visa-waiver country (eg an Indian citizen living in India), who wants to attend a Conference (in this case a few day event on a specific open source project), what kind of visa do you need?

Some bits of the Visit Canada official website section on visas talks about Visitor Visas or Business Visas, other parts talk about Tourist Visas and Business Visas, which is proving confusing (at least for me and my Indian friend...). The Business Visa sub-section does mention conferences as being something you can do on a business visa, but also they look harder to get. The Tourist Visa sub-section that you confusingly turn up on after clicking many of the Visitor Visa links doesn't seem to say anything about what you can and can't do on a tourist visa. The tourist visa page links to a Visitor Visa application form, again leading me to be confused.

(A quick google with likely keywords only found me information on what Canadians going to the USA for conferences should / shouldn't say to US immigration about their trip...)

So, hopefully simple question - Someone from a visa country (eg India) travelling to Canada to attend a conference, but who isn't doing it as a work trip (they're paying personally), what kind of visa do they need to apply for? Visitor? Tourist? Business? Other?