Bonus question: There is a tiny sliver of class D airspace surrounding
the surface B of SeaTac on the western, southern and southeastern
parts of the bravo that is surface. Anyone know if this belongs to
SeaTac because there is no other field in the center of the area and
if so, why on earth does a bravo airport also have a tiny section of
class D ...
When looking at the airspace depiction on the sectional chart, it is logical to assume that the linear portion of the edge of the transition area with 700' floor, shown by the shaded magenta boundary, continues on through the blue segmented circle around KRHV, and this controls the floor of the Class E airspace in that area when the tower is ...
The Class E transition area appears to be protecting the IAPs for RWY30L&R of KSJC. So, area #1 would be at 1200 AGL. Area #2 would be at 700 AGL. Considering the MEFs of the surrounding areas range from 3200 MSL to 4800 MSL, it may be a necessary precaution to separate the IFR traffic from the nearby Class G at the surface VFR traffic of E16.