Dropout and input headroom — what the numbers mean
The 1.3V dropout at 800mA is the worst-case figure; typical dropout at lower currents is lower, but the max is what you design to. With a 15V absolute maximum input, you have plenty of headroom for 5V or 12V rails, but the quiescent current of 10 mA is on the higher side for battery-powered designs — this part is better suited to line-powered or moderate-current applications where the Iq is a small fraction of the load.
It is a standard ST product that moves through the usual distribution channels. No LTB window to watch.