The source is required by developers to build custom ROMs and custom kernels, and also this phone has gained root access. If someday you want to restore your Sprint Photon Q 4G LTE to its stock condition as when you first take it out of the box, you can flash your phone with the stock firmware files (which commonly has *.zip; *.sbf; *.xml file extension) using RSD Lite applications.
We must appreciate to devs from xda with username Shabbypenguin and Mattlgroff, since they have provided fastboot files that compatible with RSD Lite. Their firmware files compressed in ZIP format and consists of two XML’s, the one is an standard XML that will rewrite stock bootloader and another one will not rewrite the stock bootloader when you flash it. If you aren’t familiar using RSD Lite you can head to this guide.
Update (10/6/2012): The firmware file that’s available at xda seems to have a problem, I recommend not to use the file, we should wait for devs to fix it. Go to xda-developers, download the necessary ZIP files only when the devs confirms it will work with Photon Q. Make sure you are utilizing RSD Lite v5.7 or later.