https://tsdr.uspto.gov/#caseNumber=98321164&caseSearchType=U...
https://tsdr.uspto.gov/#caseNumber=98321164&caseSearchType=U...
Good catch. Looks like it was filed just under a year ago, and hasn't been finalized yet. If it is approved, I think the original filing date is considered the registration date, so Matt's usage would (at that point) qualify as infringement. However, I am NAL.
For "ACF" however, the examiner didn't see a problem and it has been published in the Federal Register. It will be registered if no one files an opposition during the publication period.
You don't need to have a registered trademark to sue for trademark infringement; registration does make it easier to assert your trademark and can increase damage in a court case.
Whether or not that means it will be granted I have no idea. On one hand it's only known in WordPress circles. On the other hand, WordPress is said to account for over 40% of the web.
[0] https://www.reddit.com/r/Wordpress/comments/1cc0aor/what_are...