Hello,
Table /SAPAPO/LOC free attributes fields like ATTLO01 to ATTLO05 etc can be updated manually or though CIF by using enhancement through Badi SMOD_APOCF001 (Interface IF_EX_SMOD_APOCF001)
method EXIT_/SAPAPO/SAPLCIF_LOC_001.
Refer this useful wiki page,
Location - Supply Chain Management (SCM) - SCN Wiki
Best Regards,
R.Brahmankar