The supernova remnant (SNR) 30 Dor B is associated with the \ion{H}{2} region
ionized by the OB association LH99. The complex interstellar environment has
made it difficult to study the physical structure of this SNR. We have used
Hubble Space Telescope Hα images to identify SNR shocks and deep Chandra
X-ray observations to detect faint diffuse emission. We find that 30 Dor B
hosts three zones with very different X-ray surface brightnesses and nebular
kinematics that are characteristic of SNRs in different interstellar
environments and/or evolutionary stages. The ASKAP 888 MHz map of 30 Dor B
shows counterparts to all X-ray emission features except the faint halo. The
ASKAP 888 MHz and 1420 MHz observations are used to produce a spectral index
map, but its interpretation is complicated by the background thermal emission
and the pulsar PSR J0537−6910's flat spectral index. The stellar population
in the vicinity of 30 Dor B indicates a continuous star formation in the past
8--10 Myr. The observed very massive stars in LH99 cannot be coeval with the
progenitor of 30 Dor B's pulsar. Adopting the pulsar's spin-down timescale,
5000 yr, as the age of the SNR, the X-ray shell would be expanding at
∼4000 km\,s−1 and the post-shock temperature would be 1--2 orders of
magnitude higher than that indicated by the X-ray spectra. Thus, the bright
central region of 30 Dor B and the X-ray shell requires two separate SN events,
and the faint diffuse X-ray halo perhaps other older SN events