It looks a bit scary. I'm not sure the surface of the leather would survive if I tried to remove it. I should buy some and test it. It looks like useful stuff for mending shoes.
Really good for shoe repairs and a million other things. Stinks and is probably not very good for you in any form. They do a less nasty version which I haven't tried.
Shoe goo?
I had a faff sticking a car badge on and bought some 'sticks like sh*t' silicone stuff from Screwfix that would probably work well too.
Either might damage the leather on removal though so more permanant fixes.