There will be times throughout the game when you may need something that you aren’t carrying, but another player is. By attempting to move onto a square which another player is occupying, you will be asking them to swap your goods with theirs.
To find out what another player is carrying before you decide to ask them to swap goods, select their name from the Statistics menu. A dialog box will be opened showing you what they are carrying, have stored in camp, the status of their boat, their rest, hydration and nourishment factors, and what tools they have.