The tag path-length was created about two months ago in the question: Prove that there exists an another path $g$ with the same image as $f$ but length of $g = tL \forall t\in [0,1]$ where $L$ is the length of $f$. Although it has been later removed from this specific question, it was added to several other questions.
It seems that some of these questions use the word length in the sense "length of a curve". However, there already exists a tag with this meaning, namely arc-length. (And this tag exists for some time. You can find it in questions from 2015 and the taxonomist badge for this tag was awarded in 2016.) Some of these new question use this term in graph-theoretic sense, i.e., they are questions about length of a path in a graph.
The tag-info for path-length is currently empty.
What should be done about the new tag? Is it useful to have a separate tag for length of a path in a graph? (If yes, that we should explicitly explain that the new tag is for these questions and mention the tag (arc-length) in the tag-wiki as the correct tag for the other meaning of the word length.)