Finite-type concordance invariant from the framed Arf trees

Consider the sum of the trees depicted in Figure 8 of the source, associated to 2-component string links, with coefficients in $\mathbb Z/2\mathbb Z$. Framed Arf finite-type conjecture. This sum represents a non-trivial finite type concordance invariant of 2-component string links, with first non-vanishing term over $\mathbb Z/2\mathbb Z$. If true, the invariant has finite type degree $6$; finite type concordance invariants of string links through degree $5$ are known, while this degree-six case lies at the frontier of the subject.