It's 100% silicone caulk, I use Dap clear+ corn starch. You can vary the ratio depending on need. 2pts silicone to1pt cornstarch makes a putty like mix you would use if doing something like rolling out a noodle.
That pot lid in the pic above had a 1 to 3 mix, because it need to be less stiff to go in the channel. I've noticed the more starch=harder when cured and less is more elastic. Also the cornstarch makes the silicone cure really fast! With a 2to1 mix you might only have 10min to work with, maybe less.