As the question provide us a mega link first thing everybody
does is to check that link in the browser and we get a file "what_could_this_be.txt"
When you open that file you find combinations of six characters so that must be a cipher but by the looks of
it I doesn't recognise what encryption is used so
after searching on browser i found there is a js library which uses this kind of encryption
JsFuck
We just paste out file content to this site and get our flag.
Note
In linux to copy from terminal you can use xclip library.It can come handy when copy large file
content to clipboard with this command.
cat file | xclip -selection clipboard
and your file gets copy to your clipboard