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The nearest and most well-studied Lyman continuum (LyC) emitting galaxy comma Haro 11 comma offers an unparalleled opportunity to determine the conditions for LyC escape at 15-pc resolution. However comma we do not know which of the 3 dominant star-forming knots is the LyC sourcedoublePoint Knot C is a strong Ly-alpha emitter (LAE) with an ultraluminous X-ray source (ULX) Knot B hosts a very luminous ULX that is a candidate low-luminosity AGN (LLAGN) and Knot A is a starburst driving optically thin comma Green Pea-like properties. Our proposed COS spectra of the LyC will identify which of the three knots is responsible for the known LyC emission. Depending on which Knot is confirmed as the LyC emitter (LCE) comma it would illuminate the connection between LyC escape anddoublePoint LAEs and ULXs (Knot C) ULXs-LLAGN (Knot B) or Green Peas (Knot A). If Knot C is not confirmed comma then this would overturn the widely held paradigm that all LCEs must be strong LAEs. If Knot B or C is the LyC source comma then this first confirmation of a ULX LCE would imply that black hole accretion processes in dwarf galaxies may be a viable cosmological source of LyC. By establishing the LyC source in this iconic galaxy comma these observations will allow much-needed comma spatially resolved comma detailed study of the radiative transfer of LyC from the ionizing source through the local ISM. Our results will clarify understanding of LyC escape and its relation to Ly-alpha comma and inform efforts to identify LCEs at higher redshift.