Found some old notes concerning tagfiles. This all is for Slackware 14, but mainly should be useful for newer versions as well, though may have differences, I haven’t checked and compared. See below…
a_tagfile:
aaa_base:ADD
aaa_elflibs:ADD
aaa_terminfo:REC
acl:ADD
acpid:REC
attr:ADD
bash:ADD
bin:ADD
btrfs-progs:REC
bzip2:ADD
coreutils:ADD
cpio:ADD
cpufrequtils:OPT
cryptsetup:OPT
dbus:REC
dcron:ADD
devs:ADD
dialog:REC
dosfstools:REC
e2fsprogs:ADD
ed:REC
efibootmgr:REC
eject:REC
elilo:REC
elvis:ADD
etc:ADD
eudev:ADD
file:REC
findutils:ADD
floppy:ADD
gawk:ADD
genpower:OPT
gettext:REC
getty-ps:OPT
glibc-solibs:ADD
glibc-zoneinfo:ADD
gpm:REC
gptfdisk:ADD
grep:ADD
grub:REC
gzip:ADD
hdparm:ADD
hwdata:ADD
infozip:ADD
inotify-tools:REC
jfsutils:OPT
kbd:REC
kernel-firmware:ADD
kernel-generic:REC
kernel-huge:ADD
kernel-modules:ADD
kmod:ADD
less:ADD
lha:REC
libcgroup:REC
libgudev:ADD
lilo:ADD
logrotate:ADD
lrzip:OPT
lvm2:REC
mcelog:REC
mdadm:OPT
minicom:REC
mkinitrd:REC
mt-st:OPT
mtx:REC
ncompress:REC
ntfs-3g:OPT
openssl-solibs:ADD
os-prober:REC
patch:REC
pciutils:REC
pcmciautils:REC
pkgtools:ADD
procps-ng:ADD
quota:OPT
reiserfsprogs:ADD
rpm2tgz:REC
sdparm:ADD
sed:ADD
shadow:ADD
sharutils:ADD
slocate:ADD
smartmontools:ADD
splitvt:REC
sysfsutils:REC
sysklogd:ADD
syslinux:ADD
sysvinit:ADD
sysvinit-functions:OPT
sysvinit-scripts:ADD
tar:ADD
tcsh:REC
time:REC
tree:REC
udisks:REC
udisks2:REC
unarj:REC
upower:REC
usb_modeswitch:ADD
usbutils:ADD
utempter:REC
util-linux:ADD
which:REC
xfsprogs:OPT
xz:ADD
zoo:REC
ap_tagfile:
a2ps:REC
acct:OPT
alsa-utils:REC
amp:OPT
ash:OPT
at:OPT
bc:OPT
bpe:OPT
cdparanoia:OPT
cdrdao:OPT
cdrtools:OPT
cgmanager:REC
cups:REC
cups-filters:REC
dc3dd:OPT
ddrescue:OPT
diffstat:REC
diffutils:REC
dmapi:REC
dmidecode:ADD
dvd+rw-tools:OPT
enscript:OPT
flac:OPT
ghostscript:REC
ghostscript-fonts-std:REC
gphoto2:REC
groff:ADD
gutenprint:OPT
hplip:REC
htop:REC
ispell:OPT
itstool:REC
jed:OPT
joe:OPT
jove:OPT
ksh93:OPT
libx86:REC
linuxdoc-tools:REC
lm_sensors:REC
lsof:OPT
lsscsi:OPT
lxc:OPT
lzip:OPT
madplay:OPT
man:ADD
man-pages:REC
mariadb:OPT
mc:OPT
moc:OPT
most:OPT
mpg123:OPT
nano:REC
normalize:OPT
pamixer:REC
pm-utils:OPT
powertop:OPT
qpdf:REC
radeontool:REC
rpm:OPT
rzip:OPT
sc:OPT
screen:OPT
seejpeg:REC
slackpkg:REC
soma:REC
sox:REC
sqlite:OPT
squashfs-tools:REC
sudo:OPT
sysstat:OPT
terminus-font:REC
texinfo:REC
tmux:REC
usbmuxd:REC
vbetool:REC
vim:REC
vorbis-tools:OPT
workbone:OPT
xfsdump:REC
zsh:OPT
d_tagfile:
Cython:REC
autoconf:OPT
automake:OPT
binutils:ADD
bison:ADD
ccache:OPT
clisp:OPT
cmake:REC
cscope:OPT
cvs:REC
dev86:ADD
distcc:OPT
doxygen:OPT
flex:ADD
gcc:ADD
gcc-g++:REC
gcc-gfortran:OPT
gcc-gnat:OPT
gcc-go:OPT
gcc-java:OPT
gcc-objc:OPT
gdb:REC
gettext-tools:REC
git:REC
gnu-cobol:OPT
gperf:REC
guile:REC
help2man:REC
indent:OPT
intltool:REC
kernel-headers:ADD
libtool:OPT
llvm:REC
m4:REC
make:ADD
mercurial:REC
nasm:OPT
oprofile:OPT
p2c:OPT
perl:REC
pkg-config:REC
pmake:REC
python:REC
python-setuptools:REC
rcs:REC
ruby:REC
scons:REC
slacktrack:REC
strace:REC
subversion:OPT
swig:REC
yasm:OPT
l_tagfile:
ConsoleKit2:ADD
GConf:REC
LibRaw:REC
M2Crypto:REC
PyQt:REC
QScintilla:REC
a52dec:REC
aalib:REC
adwaita-icon-theme:REC
akonadi:REC
alsa-lib:ADD
alsa-oss:OPT
alsa-plugins:ADD
apr:REC
apr-util:REC
aspell:REC
aspell-en:REC
at-spi2-atk:REC
at-spi2-core:REC
atk:REC
atkmm:REC
attica:ADD
audiofile:REC
automoc4:REC
babl:REC
boost:REC
cairo:REC
cairomm:REC
chmlib:REC
clucene:REC
db42:REC
db44:REC
db48:REC
dbus-glib:REC
dbus-python:REC
dconf:REC
dconf-editor:REC
desktop-file-utils:REC
djvulibre:REC
ebook-tools:ADD
eigen2:REC
eigen3:REC
elfutils:REC
enchant:REC
esound:REC
exiv2:REC
expat:REC
fftw:REC
freetype:REC
fribidi:REC
fuse:OPT
gamin:REC
gc:REC
gcr:REC
gd:REC
gdbm:REC
gdk-pixbuf2:REC
gegl:REC
giflib:REC
glade3:REC
glib:REC
glib-networking:REC
glib2:REC
glibc:REC
glibc-i18n:OPT
glibc-profile:OPT
glibmm:REC
gmime:REC
gmm:REC
gmp:REC
gnome-keyring:REC
gnome-themes-standard:REC
gnu-efi:REC
gobject-introspection:REC
grantlee:REC
gsettings-desktop-schemas:REC
gsl:REC
gst-plugins-base:ADD
gst-plugins-base0:REC
gst-plugins-good:ADD
gst-plugins-good0:REC
gstreamer:ADD
gstreamer0:REC
gtk+:REC
gtk+2:REC
gtk+3:REC
gtkmm2:REC
gtkmm3:REC
gtkspell:REC
gvfs:REC
harfbuzz:REC
herqq:REC
hicolor-icon-theme:REC
hunspell:ADD
icon-naming-utils:REC
icu4c:REC
ilmbase:REC
iso-codes:REC
jasper:REC
jemalloc:REC
js185:REC
json-c:REC
judy:REC
keybinder:REC
keyutils:OPT
lcms:REC
lcms2:REC
libaio:REC
libao:REC
libarchive:REC
libart_lgpl:REC
libasyncns:REC
libatasmart:REC
libbluedevil:REC
libcaca:OPT
libcanberra:REC
libcap:REC
libcap-ng:REC
libcddb:REC
libcdio:REC
libcdio-paranoia:REC
libcroco:REC
libdbusmenu-qt:REC
libdiscid:ADD
libdvdnav:REC
libdvdread:REC
libevent:REC
libexif:REC
libfakekey:REC
libffi:REC
libglade:REC
libgnome-keyring:REC
libgphoto2:REC
libgpod:REC
libgsf:REC
libical:REC
libid3tag:REC
libidl:REC
libidn:REC
libieee1284:REC
libimobiledevice:REC
libiodbc:ADD
libjpeg-turbo:REC
libkarma:REC
liblastfm:REC
libmad:REC
libmcrypt:REC
libmcs:REC
libmng:REC
libmowgli:REC
libmpc:REC
libmsn:REC
libmtp:REC
libnih:REC
libnjb:REC
libnl:REC
libnl3:REC
libnotify:REC
libodfgen:REC
libogg:REC
liboggz:REC
liboil:REC
libpcap:REC
libplist:REC
libpng:REC
libproxy:REC
libraw1394:REC
librevenge:REC
librsvg:REC
libsamplerate:REC
libsecret:REC
libsigc++:REC
libsigsegv:REC
libsndfile:REC
libsoup:REC
libspectre:REC
libssh:REC
libssh2:REC
libtasn1:REC
libtermcap:REC
libtheora:REC
libtiff:REC
libunistring:OPT
libusb:REC
libusb-compat:REC
libusbmuxd:REC
libvisio:REC
libvisual:REC
libvisual-plugins:REC
libvncserver:REC
libvorbis:REC
libvpx:REC
libwmf:REC
libwmf-docs:OPT
libwnck:REC
libwpd:REC
libwpg:REC
libxklavier:REC
libxml2:REC
libxslt:REC
libyaml:REC
libzip:REC
loudmouth:OPT
lzo:OPT
media-player-info:REC
mhash:REC
mm:REC
mozilla-nss:REC
mpfr:REC
ncurses:REC
neon:REC
netpbm:REC
newt:REC
notify-python:REC
openexr:REC
openjpeg:REC
orc:REC
pango:REC
pangomm:REC
parted:ADD
pcre:REC
phonon:REC
phonon-gstreamer:REC
pilot-link:REC
polkit:ADD
polkit-gnome:ADD
polkit-qt-1:ADD
poppler:OPT
poppler-data:OPT
popt:REC
pulseaudio:ADD
pycairo:REC
pycups:REC
pycurl:REC
pygobject:REC
pygobject3:REC
pygtk:REC
pyrex:REC
python-pillow:REC
qca:REC
qimageblitz:REC
qjson:REC
qt:ADD
qt-gstreamer:REC
qtscriptgenerator:ADD
raptor2:REC
rasqal:REC
readline:REC
redland:REC
sbc:REC
sdl:REC
seamonkey-solibs:REC
serf:REC
sg3_utils:REC
shared-desktop-ontologies:ADD
shared-mime-info:REC
sip:REC
slang:REC
slang1:REC
soprano:REC
sound-theme-freedesktop:REC
speexdsp:ADD
startup-notification:ADD
strigi:REC
svgalib:REC
system-config-printer:ADD
t1lib:REC
taglib:REC
taglib-extras:REC
tango-icon-theme:REC
tango-icon-theme-extras:REC
urwid:REC
v4l-utils:REC
virtuoso-ose:ADD
vte:REC
wavpack:OPT
xapian-core:REC
zlib:REC
n_tagfile:
ModemManager:REC
NetworkManager:REC
alpine:OPT
autofs:OPT
biff+comsat:OPT
bind:REC
bluez:ADD
bluez-firmware:ADD
bootp:OPT
bridge-utils:OPT
bsd-finger:OPT
ca-certificates:REC
cifs-utils:OPT
conntrack-tools:REC
crda:REC
curl:OPT
cyrus-sasl:REC
dhcp:OPT
dhcpcd:REC
dirmngr:REC
dnsmasq:OPT
ebtables:REC
elm:OPT
epic5:OPT
ethtool:OPT
fetchmail:OPT
getmail:REC
gnupg:OPT
gnupg2:REC
gnutls:ADD
gpa:REC
gpgme:REC
htdig:OPT
httpd:OPT
icmpinfo:OPT
idnkit:REC
iftop:REC
imapd:OPT
inetd:REC
iproute2:OPT
ipset:REC
iptables:ADD
iptraf-ng:OPT
iputils:ADD
ipw2100-fw:ADD
ipw2200-fw:ADD
irssi:OPT
iw:REC
lftp:OPT
libassuan:REC
libgcrypt:REC
libgpg-error:REC
libksba:REC
libmbim:REC
libmnl:REC
libndp:REC
libnetfilter_acct:REC
libnetfilter_conntrack:REC
libnetfilter_cthelper:REC
libnetfilter_cttimeout:REC
libnetfilter_log:REC
libnetfilter_queue:REC
libnfnetlink:REC
libnftnl:REC
libqmi:REC
libtirpc:REC
links:OPT
lynx:OPT
mailx:REC
mcabber:OPT
metamail:REC
mobile-broadband-provider-info:REC
mtr:OPT
mutt:OPT
nc:OPT
ncftp:OPT
net-snmp:REC
net-tools:ADD
netatalk:OPT
netdate:OPT
netkit-bootparamd:OPT
netkit-ftp:OPT
netkit-ntalk:OPT
netkit-routed:OPT
netkit-rsh:OPT
netkit-rusers:OPT
netkit-rwall:OPT
netkit-rwho:OPT
netkit-timed:OPT
netpipes:OPT
nettle:REC
netwatch:OPT
network-scripts:ADD
netwrite:OPT
newspost:OPT
nfacct:REC
nfs-utils:OPT
nftables:REC
nmap:OPT
nn:OPT
ntp:OPT
obexftp:REC
openldap-client:REC
openobex:REC
openssh:REC
openssl:REC
openvpn:OPT
p11-kit:REC
php:OPT
pidentd:REC
pinentry:REC
popa3d:REC
ppp:OPT
procmail:REC
proftpd:OPT
pssh:OPT
pth:REC
rdist:OPT
rfkill:REC
rp-pppoe:OPT
rpcbind:REC
rsync:OPT
samba:OPT
sendmail:REC
sendmail-cf:OPT
slrn:OPT
snownews:OPT
stunnel:OPT
tcp_wrappers:REC
tcpdump:REC
telnet:REC
tftp-hpa:OPT
tin:OPT
traceroute:OPT
trn:OPT
ulogd:REC
uucp:OPT
vlan:OPT
vsftpd:REC
wget:OPT
whois:OPT
wireless-tools:OPT
wpa_supplicant:REC
yptools:OPT
ytalk:OPT
zd1211-firmware:ADD
x_tagfile:
anthy:REC
appres:REC
bdftopcf:REC
beforelight:REC
bigreqsproto:REC
bitmap:REC
compiz:REC
compositeproto:REC
damageproto:REC
dejavu-fonts-ttf:REC
dmxproto:REC
dri2proto:REC
dri3proto:REC
editres:REC
encodings:REC
evieext:REC
fixesproto:REC
font-adobe-100dpi:REC
font-adobe-75dpi:REC
font-adobe-utopia-100dpi:REC
font-adobe-utopia-75dpi:REC
font-adobe-utopia-type1:REC
font-alias:REC
font-arabic-misc:REC
font-bh-100dpi:REC
font-bh-75dpi:REC
font-bh-lucidatypewriter-100dpi:REC
font-bh-lucidatypewriter-75dpi:REC
font-bh-ttf:REC
font-bh-type1:REC
font-bitstream-100dpi:REC
font-bitstream-75dpi:REC
font-bitstream-speedo:REC
font-bitstream-type1:REC
font-cronyx-cyrillic:REC
font-cursor-misc:REC
font-daewoo-misc:REC
font-dec-misc:REC
font-ibm-type1:REC
font-isas-misc:REC
font-jis-misc:REC
font-micro-misc:REC
font-misc-cyrillic:REC
font-misc-ethiopic:REC
font-misc-meltho:REC
font-misc-misc:REC
font-mutt-misc:REC
font-schumacher-misc:REC
font-screen-cyrillic:REC
font-sony-misc:REC
font-sun-misc:REC
font-util:REC
font-winitzki-cyrillic:REC
font-xfree86-type1:REC
fontcacheproto:REC
fontconfig:ADD
fontsproto:REC
fonttosfnt:REC
freeglut:REC
fslsfonts:REC
fstobdf:REC
gccmakedep:REC
glew:ADD
glproto:REC
glu:ADD
iceauth:REC
ico:REC
imake:REC
inputproto:REC
intel-gpu-tools:ADD
kbproto:REC
libFS:REC
libICE:REC
libSM:REC
libX11:REC
libXScrnSaver:REC
libXau:REC
libXaw:REC
libXaw3d:REC
libXaw3dXft:REC
libXcm:REC
libXcomposite:REC
libXcursor:REC
libXdamage:REC
libXdmcp:REC
libXevie:REC
libXext:REC
libXfixes:REC
libXfont:REC
libXfontcache:REC
libXft:REC
libXi:REC
libXinerama:REC
libXmu:REC
libXp:REC
libXpm:REC
libXpresent:REC
libXrandr:REC
libXrender:REC
libXres:REC
libXt:REC
libXtst:REC
libXv:REC
libXvMC:REC
libXxf86dga:REC
libXxf86misc:REC
libXxf86vm:REC
libdmx:REC
libdrm:REC
libepoxy:REC
liberation-fonts-ttf:REC
libevdev:REC
libfontenc:REC
libhangul:REC
libpciaccess:REC
libpthread-stubs:REC
libva:REC
libva-intel-driver:REC
libvdpau:REC
libxcb:REC
libxkbfile:REC
libxshmfence:REC
listres:REC
lndir:REC
luit:REC
m17n-lib:REC
makedepend:REC
mesa:REC
mkcomposecache:REC
mkfontdir:REC
mkfontscale:REC
motif:REC
mtdev:REC
oclock:REC
pixman:REC
presentproto:REC
printproto:REC
randrproto:REC
recordproto:REC
rendercheck:REC
renderproto:REC
resourceproto:REC
rgb:REC
sazanami-fonts-ttf:REC
scim:REC
scim-anthy:REC
scim-hangul:REC
scim-input-pad:REC
scim-m17n:REC
scim-pinyin:REC
scim-tables:REC
scrnsaverproto:REC
sessreg:REC
setxkbmap:REC
showfont:REC
sinhala_lklug-font-ttf:REC
smproxy:REC
tibmachuni-font-ttf:REC
transset:REC
ttf-indic-fonts:REC
twm:REC
util-macros:REC
videoproto:REC
viewres:REC
wqy-zenhei-font-ttf:REC
x11-skel:REC
x11perf:REC
xauth:REC
xbacklight:REC
xbiff:REC
xbitmaps:REC
xcalc:REC
xcb-proto:REC
xcb-util:ADD
xcb-util-cursor:REC
xcb-util-errors:REC
xcb-util-image:REC
xcb-util-keysyms:REC
xcb-util-renderutil:REC
xcb-util-wm:REC
xclipboard:REC
xclock:REC
xcm:REC
xcmiscproto:REC
xcmsdb:REC
xcompmgr:REC
xconsole:REC
xcursor-themes:REC
xcursorgen:REC
xdbedizzy:REC
xdg-user-dirs:REC
xdg-utils:REC
xditview:REC
xdm:REC
xdpyinfo:REC
xdriinfo:REC
xedit:REC
xev:REC
xextproto:REC
xeyes:REC
xf86-input-acecad:REC
xf86-input-evdev:REC
xf86-input-joystick:REC
xf86-input-keyboard:REC
xf86-input-mouse:REC
xf86-input-penmount:REC
xf86-input-synaptics:REC
xf86-input-vmmouse:REC
xf86-input-void:REC
xf86-input-wacom:REC
xf86-video-amdgpu:REC
xf86-video-apm:REC
xf86-video-ark:REC
xf86-video-ast:REC
xf86-video-ati:REC
xf86-video-chips:REC
xf86-video-cirrus:REC
xf86-video-dummy:REC
xf86-video-glint:REC
xf86-video-i128:REC
xf86-video-i740:REC
xf86-video-intel:REC
xf86-video-mach64:REC
xf86-video-mga:REC
xf86-video-neomagic:REC
xf86-video-nouveau:REC
xf86-video-nv:REC
xf86-video-openchrome:REC
xf86-video-r128:REC
xf86-video-rendition:REC
xf86-video-s3:REC
xf86-video-s3virge:REC
xf86-video-savage:REC
xf86-video-siliconmotion:REC
xf86-video-sis:REC
xf86-video-sisusb:REC
xf86-video-tdfx:REC
xf86-video-tga:REC
xf86-video-trident:REC
xf86-video-tseng:REC
xf86-video-v4l:REC
xf86-video-vesa:REC
xf86-video-vmware:REC
xf86-video-voodoo:REC
xf86-video-xgi:REC
xf86-video-xgixp:REC
xf86bigfontproto:REC
xf86dga:REC
xf86dgaproto:REC
xf86driproto:REC
xf86miscproto:REC
xf86vidmodeproto:REC
xfd:REC
xfontsel:REC
xfs:REC
xfsinfo:REC
xgamma:REC
xgc:REC
xhost:REC
xineramaproto:REC
xinit:REC
xinput:REC
xkbcomp:REC
xkbevd:REC
xkbprint:REC
xkbutils:REC
xkeyboard-config:REC
xkill:REC
xload:REC
xlogo:REC
xlsatoms:REC
xlsclients:REC
xlsfonts:REC
xmag:REC
xman:REC
xmessage:REC
xmh:REC
xmodmap:REC
xmore:REC
xorg-cf-files:REC
xorg-docs:REC
xorg-server:REC
xorg-server-xephyr:ADD
xorg-server-xnest:REC
xorg-server-xvfb:REC
xorg-sgml-doctools:REC
xpr:REC
xprop:REC
xproto:REC
xpyb:ADD
xrandr:REC
xrdb:REC
xrefresh:REC
xscope:ADD
xset:REC
xsetroot:REC
xsm:REC
xstdcmap:REC
xterm:REC
xtrans:REC
xvidtune:REC
xvinfo:REC
xwd:REC
xwininfo:REC
xwud:REC