What is unique to California tax law regarding material participation in rental real estate activities starting in $1994?$

There is nothing unique to California tax law, because they are in conformity with the IRC in regards to rental real estate activities.

California tax law, unlike the federal, treats rental real estate activities as though they were active economic activities.

California tax law changed the depreciation conventions for real property in connection to rental real estate activities in $1994,$ unlike the federal which has adopted the MACRS system for depreciating assets since $1987.$

California tax law, unlike the federal, treats rental real estate activities as passive, even though the federal equivalent allows some level of persons operating in real property businesses to not automatically treat such activity as passive.