I need to investigate that but I think that sailfish-browser uses the mozilla way to save history. If its a sqlite database I only need to investigate how it is structured to make it show up also in webcat.
Though I am not sure how to access the database file without hardcoding the path somehow to $home/.mozilla/mozembed .
But needs investigation. Keep you updated

PS: found out they save as sqlite in $home/.local/org.sailfishos/sailfish-browser . Working on an integration.
P.P.S: Won't make it into webcat 1.0 though as the sqlite database access needs its own c++ class. I put it on the todo list for post 1.0