If you start the "Mombasa Streets" CM and save the "Tayari Plaza" mission for last, when you complete it you will find yourself locked in District 5 with a beacon to the Data Hive mission situated on that door. That may be why the button is there.
There are six possible entries to the Data Hive from Mombasa Streets. It has not been confirmed yet, but I'm guessing that all six show buttons like the one you found. Wanna help test this?!? Check out ApolloDoom's image of the entry to Data Hive in District 3
here in the Gallery. A simple trip back there in Mombasa Streets will tell us.
I'll make a District 05 album and upload your image to it- thank you! If you want to take more images of the "Data Hive Doors", please share them! It would be nice to have a whole collection of them in the Gallery for everyone's reference.