Turns out, however, Apple did eventually publish the extension — they just never told us. We don’t know when it happened, but it was likely around or after Thanksgiving, because we’d checked a few times since receiving that last email saying we were still under review.
There’s very few cool/new extensions for Safari nowadays. This dev makes the case that it’s a terrible experience for programmers. iOS/Mac codebase consolidation is likely the cause, and again, the Mac gets a downgrade in experience because of it.