If you click on any logos on page 4 of the pdf it redirects to a Dropbox file but I guess it’s not very well precised so yeah I’d say your post will still be helpful for finding the ON ROBLOX branding quicker.
By black on white I meant just like a light mode version of the logo
To add to this, I’ve made two thumbnail designs on Canva that everyone can use to make their thumbnails. These two designs follow the rules of logo positioning.
I would also recommend people to use this size as an experience thumbnail format because I often see people have a too small or too big image that totally doesn’t fit into the experience page.