My question involves real estate located in the State of: California

I know this is a popular topic and has been brought up many times, but I'm very confused about responsibility of retaining wall maintenance.

My home was built in 1911 and would be considered the "uphill property". The neighboring building was built in 1924. I don't know for sure when the retaining was was built but suspect it was built at the time the neighboring property was developed so they would have a flat lot to build on. And given the laws regarding the right to lateral and subjacent support, I suspect it was built with that in mind.

It's difficult to tell without a survey where exactly the wall sits in relation to the property line. But lets say for argument sake, that it is built on my property and the outside facing side of the wall serves as the property line. Does it really matter where the wall sits that defines the responsibility for maintenance? It seems to me that my right to lateral support and the downhill neighbor's obligation to provide it wouldn't go away simply because someone placed the retaining wall on my property. Will look for some case law but would appreciate feedback. Thanks