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Ultra diffuse galaxies (UDGs) --- a remarkable class of low-surface brightness galaxy --- have been recently discovered in large quantities comma possessing large physical sizes (>2 kpc) comma yet low central surface brightness (virgul25 mag-arcsecelev2) and stellar mass (<10elev8 M_sun). These galaxies comma abundant in groups and clusters comma are completely distinct from normal galaxy populations comma suggesting formation mechanisms that are unexpected comma yet important for galaxy evolution. Substantial HST time has been spent to better understand UDGs as a population. Yet comma nearly every known UDG is too distant to resolve their stellar populations comma which are likely crucial to understanding their origins. Only one known UDG is close enough to study in detaildoublePoint F8D1 is a member of the M81 group and only 3.7 Mpc away. We propose a deep comma benchmark survey of F8D1.s stellar populations --- a crucial case study of UDG formation physics and of the various models of UDG formation comma including tidal processing and unique SFHs. This proposal targets two deep comma coordinated ACS-WFC3 fields comma as well as a map extending out to larger radii which will allow us to search for faint signatures of tidal disruption. In 31 orbits comma we will provide the first-ever measure of a UDG.s resolved SFH comma as well as its SFH gradient comma and will constrain the presence of any tidal signatures within 5*R_eff comma down to the deepest-ever (virgul33 mag-arcsecelev2) surface brightness limit. With a fraction of the current HST investment comma we will conduct the first 'Rosetta Stone. investigation of a UDG. This high legacy-value resolved-star dataset will be key to deciphering the complex potential avenues leading to the formation of these enigmatic galaxies.