Until recently, the tag python was the only tag for the Python programming language. Now there’s also a python3 tag:
OP tagged this question with python3 (new tag, only used in this question).
I retagged the question with python (used in 45 questions), edit-commenting: "no need for a "python3" tag (can be specified in the question)".
OP (accidentally) retagged it again.
Do we want to have version-specific programming language tags?