A change of a grid's rows, as Masu.History keeps it:
grid- the grid's id;row_id- the row's id, as the browser has it;key- the column's key; nil for the row (op:createor:delete);op-:update(a cell),:createor:delete(a row);beforeandafter- the cell's value before and after, as the browser gets them (Masu.Wire); for a row, its cells' values by column key;user_idanduser_name- who, from the grid'suser;origin- what they did, asMasu.Write'soriginsays (:edit,:paste,:restore...);batch- the write it was part of;at- when;id- the store's id of it.