Aren't developer salaries, servers, etc., included in that? That's what I seem to recall from recent tax changes that were discussed here a few weeks ago.
Developer salaries are probably under Research & Development, further, given their employee count and likely mix of tech (it/dev/infra) to biz, that's the only line item likely large enough to house their engineering team.
> Cost of revenue consists primarily of payments to third parties for the cost of hosting and supporting our mobile applications and website. In addition, cost of revenue includes expenses directly associated with the delivery of our advertising and other services, including advertising measurement services and credit card and other transaction processing fees. Cost of revenue also consists of personnel-related costs, including salaries, benefits, and stock-based compensation.