$ grep SYSTEM_SETTING apps/settings_list.c
#define SYSTEM_SETTING(flags,var,default) \
    SYSTEM_SETTING(NVRAM(4),resume_index,-1),
    SYSTEM_SETTING(NVRAM(4),resume_first_index,0),
    SYSTEM_SETTING(NVRAM(4),resume_offset,-1),
    SYSTEM_SETTING(NVRAM(4),resume_seed,-1),
    SYSTEM_SETTING(NVRAM(4),runtime,0),
    SYSTEM_SETTING(NVRAM(4),topruntime,0),
    SYSTEM_SETTING(NVRAM(4),last_frequency,0),
    SYSTEM_SETTING(NVRAM(4),dircache_size,0),
    SYSTEM_SETTING(NVRAM(1),last_screen,-1),
    SYSTEM_SETTING(NVRAM(4),filetype_count, MAX_FILETYPES),