EdgeTaggedGraphQ
EdgeTaggedGraphQ[g] yields True if the graph g has edges tagged and False otherwise.
Examples
EdgeTaggedGraphQ[Graph[{1 <-> 2, 2 <-> 3}]]
(* False *)g = Graph[{Property[1 <-> 2, EdgeTags -> {"a"}], 2 <-> 3}];
EdgeTaggedGraphQ[g]
(* True *)Please visit the official Wolfram Language Reference for more details.