This tag is for the TikZ angles library.
This library defines pic types for drawing angles.
This pic adds a drawing of an angle to the current path. This “drawing of an angle” consist of a “sector” or “wedge” or “slice” whose pointed end is at point (B) and whose straight sides lie on the lines form (B) to (A) and from (B) to (C).
The three points (A), (B), and (C) must be the names of nodes or coordinates; you cannot use direct coordinates like “(1,1)” here.