Thank you Rodolfo for the quick answer.
I raised those concerns because you, as a person, are requesting to join the PHP-FIG as a representative of your project, and that's not only the project that is under scrutiny. I personally, being a secretary, don't even have the right to vote on your membership, but I wanted these concerns addressed so that everyone with voting rights could decide if and how to weight those on your membership request.
Clarification: these below are my personal considerations, that aren't in any mean intended as a PHP-FIG official opinion.
You answered that you "didn't intend" to infringe on copyright or trademarks, but to the eye of the law that doesn't matter, you're still committing copyright/trademark infringement, and it's a pretty clear and cut case, since you're using companies' trademarks, which IIRC aren't even covered by rules like fair use. You can't consider yourself in the right just because none of these companies haven't discovered you or bothered to issue a cease and desist to you, you're still infringing. And open source, the very core mission or PHP-FIG, is founded on copyright licenses, so I'm worried of your low consideration on this topic.
I welcome your clarification on xrdebug, and I've also seen on Reddit that you consider it an open source alternative to Spatie's Ray, not to a full fledged debugger; but still, you're using a name that very closely resembles an established, widely known and copyright-covered tool, which is possibly not trademarked only because Derick didn't have the funds to register it; this is even a bit worse once we consider it not a proper debugger, because it makes me question further why you decided for such a name.