> Clearly AdvancedCustomFields should have filed a trademark to prohibit Wordpress from fully stealing it.

They did:

Advanced Custom Fields — https://tsdr.uspto.gov/#caseNumber=98321164&caseSearchType=U...

ACF — https://tsdr.uspto.gov/#caseNumber=98321135&caseSearchType=U...

Oh nice. Then WordPress shouldn’t be able to take over without renaming, right?

they renamed to "secure custom fields"

They kept the permalink afaik, which is probably still likely to cause confusion in the marketplace and may still be a trademark issue.

Without knowing this drama, if I found and clicked an ACF link on a 2 year old Reddit post and ended up at Secure Custom Fields, I’m not sure I’d know it wasn’t by the ACF folks. Just their branding for the v2 or whatever. I think customers have a reasonable expectation that permalinks won’t take them to unrelated products.

Yep. And the string 'acf' is used throughout the plugin and the plugin download page (in reviews, etc). And 'acf' is indeed a pending trademark registration.

Not good.

Very much doubt they will be able to trademark “acf”.