Authorizing the revision of lines and grades on a portion of City Plan No. 123 by relocating the northerly houseline of Montgomery Avenue from Fifteenth Street to Broad Street, thereby reducing the width of said Montgomery Avenue and relocating the easterly houseline of Fifteenth Street from Montgomery Avenue to a point approximately three-hundred thirty-one feet northwardly therefrom, thereby reducing the width of said Fifteenth Street, under certain terms and conditions. — Open Common Ground