Its probably on the back.
Thats a 3 wire range cable , aluminum conductors & an old 50 amp outlet . it will have 2 conductors & a braided bare conductor for the ground .
50 amps is a rather large load to use for lighting unless your running around 10, 000 watts . you could get a 50 amp 240 volt controller made for it but you'll have no neutral for conveniance outlets .
i'd say leave it be & run new circuts to your room , you have room in the panel for a couple breakers if you pull that 50 amp breaker out .