mysqli savepoint rollback support missing

Am I missing something or is rollback support for savepoints missing from
the mysqli extension?
The commit that added savepoint
support (666a83566077d1db195fd17d088062434b6202fa) is named "Add savepoint
and rollback to savepoint support" yet only adds the ability to create new
savepoints and release them (remove without rollback or commit). It does
not add the ability to rollback to a savepoint with a "ROLLBACK TO"
statement, and the "rollback" method with the savepoint name as the "name"
parameter doesn't seem to accomplish this goal either.