What are they and what are their intended uses? Does anyone have notes/slides of this talk?

I am curious about "log motives" because there seems to exist a "log motivic yoga" among experts in arithmetic geometry, but I could find only a few short hints and no available exposition or survey. E.g. in Asterisque 223, Fontaine lists a text about them in the bibl. of his artcles, Niziol mentions them shortly in her p-adic semi-stability conjecture (a p-adic analogon of Grothendieck's l-adic local monodromy theorem).