If you have enabled the team history information for assigning, either by default or on demand, you will presented with a lot of information. In order to not take up a lot of space, the information is compacted into a fairly dense format. This page describes how to read the information.
The team history information considers the game level and game type when deciding to count the number of times a person has seen a particular team. For example, with Boys JV will not count against Boys V, Girls V will not count the same as Boys V, etc.
The location history doesn't consider anything about the game aside from its location.
In addition to the counts provided, the date of the most recent and/or next assignment relative to the current game will be shown so you can decide if it has been enough time since the official has seen that team.
Example Listing:
H:3-1, 11/10, V:0:2, 10/21, @5 12/3
Starting from the left, this say that the official has seen the current game's home team 3 times at home and 1 time on the road. The last time the official had seen the team was on 11/10.
Next, this official has seen the visiting team for this game 0 times at the visiting team's home and 2 times as a visitor somewhere. The last time the official had seen this team was on 10/21.
Lastly, this official has been to this game's location 5 times, the last of which was on 12/3.
These items can be enabled while assigning by clearing the "Location History" and "Team History" boxes or can be enabled by default under your profile settings.