Understanding RAM-, CPU- and FDs-related metrics of postgres_exporter

Question

I'm using prometheus postgres_exporter to monitor PostgreSQL database, version is v0.15.0.

There are RAM-, CPU- and FDs-related metrics:

# HELP process_cpu_seconds_total Total user and system CPU time spent in seconds.
# TYPE process_cpu_seconds_total counter
process_cpu_seconds_total 0.09

# HELP process_max_fds Maximum number of open file descriptors.
# TYPE process_max_fds gauge
process_max_fds 1.048576e+06

# HELP process_open_fds Number of open file descriptors.
# TYPE process_open_fds gauge
process_open_fds 11

# HELP process_resident_memory_bytes Resident memory size in bytes.
# TYPE process_resident_memory_bytes gauge
process_resident_memory_bytes 1.077248e+07

# HELP process_start_time_seconds Start time of the process since unix epoch in seconds.
# TYPE process_start_time_seconds gauge
process_start_time_seconds 1.69955861358e+09

# HELP process_virtual_memory_bytes Virtual memory size in bytes.
# TYPE process_virtual_memory_bytes gauge
process_virtual_memory_bytes 1.26656512e+09

# HELP process_virtual_memory_max_bytes Maximum amount of virtual memory available in bytes.
# TYPE process_virtual_memory_max_bytes gauge
process_virtual_memory_max_bytes 1.8446744073709552e+19

How to understand, does these metrics shows PostgreSQL (database) process resources consumption, or postgres_exporter (just an exporter itself) process resources consumption?

I suspect that these are exporter resources, because RAM consumption is low (ones-to-tens of megabytes, versus hundreds of megabytes that would be typical for a database daemon). But this is just a wild guess.