The maintenance and repair of sidewalks is the responsibility of the property owner per Section 5610 of the California State Street and Highways code and Section 12.04 of the Oakland Municipal Code. These codes require property owners to repair and maintain their sidewalks, except where sidewalk damage is caused by an official City of Oakland tree, in which case the City's current policy is to take on those repairs. If sidewalks are nonexistent, then the owners of the adjacent parcel are responsible for the installation of new sidewalks.

STREET AND HIGHWAYS CODE.
5610. The owners of lots or portions of lots fronting on any
portion of a public street or place when that street or place is
improved or if and when the area between the property line of the
adjacent property and the street line is maintained as a park or
parking strip, shall maintain any sidewalk in such condition that the
sidewalk will not endanger persons or property and maintain it in a
condition which will not interfere with the public convenience in the
use of those works or areas save and except as to those conditions
created or maintained in, upon, along, or in connection with such
sidewalk by any person other than the owner, under and by virtue of
any permit or right granted to him by law or by the city authorities
in charge thereof, and such persons shall be under a like duty in
relation thereto.

The PWA Call Center has answered partially by quoting the CA code, which includes the following, "... If sidewalks are nonexistent, then the owners of the adjacent parcel are responsible for the installation of new sidewalks."
Has the City of Oakland approached the owner's of the adjacent parcel to require the installation of a sidewalk? If not, this item is still open.

This issue is similar to the following reported item:
Oakland Public Works Service Request ID: 415316 - Block of W Grande lacks sidewalk.
This item references the next block of West Grande, between Magnolia and Adeline.

The City of Oakland addressed this issue on 10/31/2021, service request #415315.