As requested:
jrg@raspi4:~ $ cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 10 (buster)"
NAME="Raspbian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=raspbian
ID_LIKE=debian
jrg@raspi4:~ $ sudo journalctl --no-pager -u lighttpd
-- Logs begin at Fri 2020-11-06 11:08:56 AEDT, end at Sat 2020-11-14 06:05:40 AEDT. --
Nov 06 11:09:00 raspi4 systemd[1]: Starting Lighttpd Daemon...
Nov 06 11:09:00 raspi4 systemd[1]: Started Lighttpd Daemon.
Nov 13 07:14:44 raspi4 systemd[1]: Stopping Lighttpd Daemon...
Nov 13 07:14:44 raspi4 systemd[1]: lighttpd.service: Succeeded.
Nov 13 07:14:44 raspi4 systemd[1]: Stopped Lighttpd Daemon.
Nov 13 07:14:44 raspi4 systemd[1]: Starting Lighttpd Daemon...
Nov 13 07:14:44 raspi4 lighttpd[2102]: 2020-11-13 07:14:44: (server.c.1493) WARNING: unknown config-key: deflate.mimetypes (ignored)
Nov 13 07:14:44 raspi4 systemd[1]: Started Lighttpd Daemon.
Nov 13 10:07:58 raspi4 systemd[1]: Stopping Lighttpd Daemon...
Nov 13 10:07:58 raspi4 systemd[1]: lighttpd.service: Succeeded.
Nov 13 10:07:58 raspi4 systemd[1]: Stopped Lighttpd Daemon.
Nov 13 10:07:58 raspi4 systemd[1]: Starting Lighttpd Daemon...
Nov 13 10:07:59 raspi4 lighttpd[12797]: 2020-11-13 10:07:58: (server.c.1493) WARNING: unknown config-key: deflate.mimetypes (ignored)
Nov 13 10:07:59 raspi4 systemd[1]: Started Lighttpd Daemon.
jrg@raspi4 : ~ $ ls -la /etc/lighttpd/conf-enabled
total 8
drwxr-xr-x 2 root root 4096 Nov 13 10:07 .
drwxr-xr-x 4 root root 4096 Nov 5 16:44 …
lrwxrwxrwx 1 root root 47 Oct 2 14:58 88-dump1090-fa-statcache.conf → …/conf-available/88-dump1090-fa-statcache.conf
lrwxrwxrwx 1 root root 47 Jul 19 14:52 88-graphs1090.conf → /etc/lighttpd/conf-available/88-graphs1090.conf
lrwxrwxrwx 1 root root 44 Nov 13 10:07 88-tar1090.conf → /etc/lighttpd/conf-available/88-tar1090.conf
lrwxrwxrwx 1 root root 52 Nov 13 10:07 88-tar1090-persist.conf → /etc/lighttpd/conf-available/88-tar1090-persist.conf
lrwxrwxrwx 1 root root 39 May 22 14:20 88-timelapse1090.conf → …/conf-available/88-timelapse1090.conf
lrwxrwxrwx 1 root root 37 Oct 2 14:58 89-dump1090-fa.conf → …/conf-available/89-dump1090-fa.conf
lrwxrwxrwx 1 root root 42 Feb 14 2020 90-javascript-alias.conf → …/conf-available/90-javascript-alias.conf
lrwxrwxrwx 1 root root 54 Nov 13 10:07 95-tar1090-otherport.conf → /etc/lighttpd/conf-available/95-tar1090-otherport.conf
jrg@raspi4 : ~ $ grep mod_setenv /etc/lighttpd/ -rnT
/etc/lighttpd/conf-available/87-mod_setenv.conf: 1: server.modules += ( " mod_setenv " )
/etc/lighttpd/conf-available/89-dump1090-fa.conf: 42: server.modules += ( " mod_setenv " )
(Sorry I've got myself caught in quote format and can't escape! - will post a second reply with the rest...)