The grants came from our token fund, not users' tokens (no way to buy BAT then).
The issue which I found out about late, and fixed right away, was infringing on right to publicity, nothing to do with donations from users' own tokens.
That blog post is about a partnership (which ended), but you probably saw some sponsored images at the time, in new tab pages (1 of 4 then, I think; the rest are just art images).
These are non-tracking, carefully designed (including vetting by Brave), brand advertising images. They are not ads (we never did this) inserted into publisher pages, or (opt-in only) push notifications.
Brave has been working to find ways to sustain ourselves, and these sponsored images are still a good revenue line, although lesser now vs other lines. If you want, turn them off.
Free riding is always an user right, we don't try to stop it on principle, as if we ever could with open source. But there's no free lunch: if you use Firefox, you are Google's product. If you use a Firefox fork, you're free riding on Gecko which costs a lot to maintain. HTH
I don't know what "semantic HTML enrichment" means, but there wasn't time. The alternative was VBScript and DHTML. DHTML and Netscape's DOM forked Web content based on `if (document.all) /* IE code here */; else /* netscape code here */`, and only with Firefox, Opera, and Safari founding whatwg.org and start HTML5 did we unify everything.
The issue which I found out about late, and fixed right away, was infringing on right to publicity, nothing to do with donations from users' own tokens.