How PornHun or Other sites use INDIRECT links

Hello Gangs....i'm new in the forum....
i gotta ask aload of question...
Everyone has Visited PORNHUB.... and if you join the website(pornhub) you'll be able to download videos with Direct links...
but there is something special.....

Links do not End in an EXTENTION....
for example : domain/videoname.mp4 <==== not in this way...
- - - -- -
They are in this Way === > domain/videoname.mp4/tdrfdsfsf/aadf3211/sdf/e=122654

i mean... the Construction or...the instruction on every Download link is indirect....
i just wanna know how they make this happen....
and which script do they use ?