Currently tablet doesn't have any use i think (in earlier version it was showing what task were left), and after you unlock security room in mixy cave next to exit door will show up, there you can use the key to see an ester egg. Btw code to fremy vip scene is 1bunny 2carrot 3heart
I guess I should make my answer clearer before. The red key is for the secret door next to exit that show up after turning on all the fuse boxes. I gave the code so anyone else wondering what it is had it already
Not sure if it's only in paid version(Wich I'm plaing on) or not but for it you need fremys vip pass(or whatever was ot called) and mabey fuse box on but not sure about second one
