Yellow mark on minimap

Hey,

Sometimes in multiplayer game on minimap appears a yellow sqares marker.
What is it and how to call this mark?
I have a feeling that some players call this mark themselves to signal something on minimap to the other players.

Yes it is to signal something on minimap to the team players, like: team, we attack here … I personally can’t see it very useful, but I’m newbie in 1v1, Team x Team.
ALT+Lclick does it.

Thank you very much for the explanation

You mean holding ALT and mouse left click on minimap?
When I call this signal I will see it too?

The only people who can see a minimap ping are those who you have allied and have shared vision with.