The PostgreSQL install location is OS-specific:
Linux:
/usr/local/pfx/pgsql
Mac:
/Applications/pfx/pgsql
Windows (all versions):
C:\Program Files\pfx\pgsql
The data directory, configuration file, and log file are all located relative to the PostgreSQL install folder, <PGSQL_DIR>:
data: <PGSQL_DIR>/data
conf: <PGSQL_DIR>/data/postgresql.conf
log: <PGSQL_DIR>/pgsql.log