alt Hacker NewsWell obviously salaries will be the highest expense in any organization like this. The more interesting question is if it's salaries to security programmers or teachers at an african womens' coding bootcamp (yes they did spend money on that, and yes it's probably useful, but hardly what people think of when they see those "donate now to keep wikipedia alive" banners). A big percentage probably goes to their CEO who does who knows what.
There are a couple of ways to approach this information. One is to compare to the past. For example, comparing with 2008-2009 [1], they now spend 3.75 times as much on hosting, but 48 times as much on salaries, illustrating a more-than-tenfold relative growth in salaries compared to hosting. While hosting is not now nor ever was their only relevant expense, it is a good anchor point.
Another key difference over the last 15 years has been the introduction of awards and grants, which didn't exist then but now comprise $26.8M (15%) of their expenditures. This is where most of the ideological/controversial spending actually goes, rather than the salaries per se, but even more to the point, this one line item is more than 3 times their entire inflation-adjusted budget from 15 years ago ($5.6M times 150% CPI = $8.4M) and is still more than if we adjusted their entire budget using the hosting cost as an index ($5.6M times 3.75 = $21M).
[1]: https://upload.wikimedia.org/wikipedia/commons/a/a4/WMF_Annu...