BUG #16049: log_line_prefix=%a and log_connections - application_name missing

The following bug has been logged on the website:

Bug reference: 16049
Logged by: death lock
Email address: deathlock13(at)gmail(dot)com
PostgreSQL version: 9.5.19
Operating system: Debian 11
Description:

[unknown] LOCATION: BackendRun, postmaster.c:4300
[unknown] DEBUG: 00000: InitPostgres
[unknown] LOCATION: InitPostgres, postinit.c:555
[unknown] DEBUG: 00000: my backend ID is 4
[unknown] LOCATION: SharedInvalBackendInit, sinvaladt.c:324
[unknown] DEBUG: 00000: StartTransaction
[unknown] LOCATION: ShowTransactionState, xact.c:4975
[unknown] DEBUG: 00000: name: unnamed; blockState: DEFAULT; state:
INPROGR, xid/subid/cid: 0/1/0, nestlvl: 1, children:
[unknown] LOCATION: ShowTransactionStateRec, xact.c:5004

# log_connections - application_name MIA
[unknown] LOG: 00000: connection authorized: user=postgres
database=postgres

[unknown] LOCATION: PerformAuthentication, postinit.c:257
psql DEBUG: 00000: CommitTransaction
psql LOCATION: ShowTransactionState, xact.c:4975
psql DEBUG: 00000: name: unnamed; blockState: STARTED; state:
INPROGR, xid/subid/cid: 0/1/0, nestlvl: 1, children:
...
psql DEBUG: 00000: proc_exit(0): 4 callbacks to make
psql LOCATION: proc_exit_prepare, ipc.c:187

# log_disconnections=on
psql LOG: 00000: disconnection: session time: 0:00:10.280 user=postgres
database=postgres host=[local]