OS X users digging through today’s beta update to the system have discovered what appears to be a reference to an as-of-yet unannounced version of the iMac. The model, dubbed iMac 15,1 could be shown off next week at Apple’s WWDC conference, where we’ve heard that there will likely be some new hardware announcements.

More specifically, the following lines were added to a power management file in the new beta:

Tweetbot for Mac

Mac-81E3E92DD6088272.plist / iMac15,1 (IGPU only) Mac-42FD25EABCABB274.plist / iMac15,n (IGPU/GFX0/Apple display with id 0xAE03) Mac-FA842E06C61E91C5.plist / iMac15,n (IGPU/GFX0/Apple display with id 0xAE03)

The 15,1 designation refers to a model that doesn’t exist yet (as the current-generation iMacs are designated 14,1 and 14,2 based on display size). Whether we’ll see any other hardware at next week’s conference is still unknown, but there don’t seem to be any other unreleased models included in the 10.9.4 update.

The fact that the machine is included here means that it will likley see a release soon, possibly even the same day as the WWDC keynote. As usual, we’ll have live coverage of the WWDC keynote and all of Apple’s announcements on June 2nd.

Update: It appears that today’s 10.9.4 beta has been pulled from the Mac Dev Center.