Has the same relation to NL as P/poly does to P.
Is contained in ⊕L/poly [GW96], as well as SAC1.
Has the same relation to ⊕L as P/poly does to P.
Has the same relation to UL as P/poly does to P.
Equals NL/poly [RA00]. (A corollary is that UL/poly is closed under complement).
Note that in UL/poly, the witness must be unique even for bad advice. UL/mpoly (as in BQP/mpoly) is a more natural definition, but this is a moot distinction here because [RA00] show that they both equal NL/poly.