v1.9.1 does NOT change any of the LSST filter throughputs. The v1.9.0 versions already include as-measured values for the mirrors, lenses and filters, as well as reasonable average detector throughputs (per vendor; the "average" detector used by default is a joint-minimum and thus does not represent any single detector exactly). These throughputs, especially when replacing the average detector with a particular vendor detector, agree fairly well with measurements from the system to date.
This patch does include additional extra throughput curves -- in particular Cousins R and I bands -- in order to facilitate comparison of LSST photometry to catalogs from other systems.