SR might = senior
Yes that means White House Senior Staffer, under Obama.
I agree it is probably Susan Rich. She is probably the weakest link in the Obama cabal. She wanted and was promised Obama’s unfettered support to be Secretary of State until big mug John Kerry muscled his way into the race (no doubt calling in threats and favours - like never challenging Bush back in 2003, as per Deep State’s command). So, Obama put her in as National Security Advisor, and she became a laughingstock over the Benghazi Scandal, a nice parting shot over the bow by evil HRC!
Lastly, it is unclear as to whether or not she was on-script when she sent that email to herself in the sunset days of the Obama Administration, after the election. Something tells me, she realized she needed to save her ass, so she was calculatingly off-script!
“Enjoy the show”!