Ned to understand why all the idle connections

Hi:

psql (9.6.7, server 11.3) on linux

I have what appear to be a log of idle connections to my DB.  Query of pg_stat_activity indicates well over half (127/206) are like this...

dvdb=# select state_change,wait_event_type,wait_event,state,backend_type from pg_stat_activity where query = '';
         state_change          | wait_event_type |     wait_event      | state |         backend_type        
-------------------------------+-----------------+---------------------+-------+------------------------------
 2020-04-23 12:57:58.215854-04 | Client          | ClientRead          | idle  | client backend

What does this indicate?

The vast majority of the connections are through perl/dbi.   If a connection is made, and is currently not doing anything, does it appear in pg_stat_activity as "idle" ?  If, in DBI, $dbh->disconnect is used whenever the DB is no longer needed, will it disconnect from the DB and NOT appear as an idle in pg_stat_activity ?

If there are any other column s in pg_stat-activity you'd like to see, or any other query in any of the system tables, please advise.

Thanks!