When I try to message a user who has posted an item that I want, it'd be useful if there's a place to see which items of mine they liked. This way I don't have to scroll through all their likes list searching for my posted items. Some people's like lists are really long.
Similarly, having the ability to see which items of theirs I liked too, would be handy. It might spur more bundle trades or encourage people to use their likes list and keep them up to date.
Posted a general idea of what it could look like. I'm not a designer. I just cobbled together a rough idea based on existing styles.