The graph search in Re^11: Finding All Paths From a Graph From a Given Source and End Node is a branch and bound algorithm, i.e. it returns values which are processed by the caller.

A Tail call is a subroutine ... that produces a return value, which is then immediately returned by the calling procedure.

Writing the branch and bound as iteration is always possible but is IMHO not necessarily a tail call.

(though in this case it could be possible to transform it into a tail call)