When your release keeps getting pushed back to get other customer facing releases out the door, but your project is vital to every product's functionality and your just sitting there like...

Why would they push it back if it is vital to the functionality of the other customer facing products? I would think it should be on the critical path in the master project plan?

Nobody really knows what it is, since it isn't an actual product...

Sounds like a conundrum one of my coworkers deals with regularly.

I call your role "the bass player". You provide the most critical element to the production but nobody notices you until you fuck up. Lack of attention from the lead singer (PM) is an indication that your good at your job. Rock on!