In the past it was sales&marketing only with smattering of a few "guest desks" for visiting engineers. And the site leads at Waterloo (at least) lobbied hard to prevent Toronto from ever really having engineering for real. Probably out of worry about centre of gravity being sucked away, etc.

IMHO it limited Google's hiring ability in Ontario. And it made me (and others) have to sell my house in Toronto and move when my employer was acquired. I tried the van/bus commute for 6 months and it was too hard.

Then the Geoffrey Hinton folks moved in there I believe. And I think some AI R&D was happening there?

And then COVID happened, and everyone was WFH but when you did go into the office and book a desk, it became possible to go into the Toronto office instead.

I left after that so can't say how it is now. Google goes through waves of "defrags" where small groups and teams in peripheral offices are... purged and merged because there's a feeling that "strength in numbers" for a particular project pays off. I wouldn't be surprised to see what happen post-layoffs.

The Toronto office, when I visited it, was small. Food was good though.