Ok, this can be tricky if you don't play around with the menu items, but it works for both chrome-ish and mozilla-like browsers the same way:
On a webm's thumbnail, if you copy the link address
for instance, you'll get the following. This passes the webm through a player file: https://sushigirl.tokyo/player.php?v=/tunes/src/1444087705547.webm&t=%E3%82%BD%E9%80%A3%E8%BB%8D%20The%20great%20power%20of%20soviet%20army%21.webm&loop=1
If you save video as...
or open video in new tab
, this will link directly to the webm, like so: https://sushigirl.tokyo/tunes/src/1444087705547.webm
Use the image attached as a guide: Upper part of the menu plays the webm/deals with a playable link to it through player.php, whereas the lower part links directly to the file itself for, say, download. I hope my wonky explanation helped!