Udev missing

[ebusch8]

I was following the guide in the readme at
packages/sdk-cli/README.md
and I saw this:

Usage on Linux

If you're using these tools on Linux, there's a couple extra steps you may need to take. These could vary a little dependent on what distro you use. The steps below are for Ubuntu and derivatives but you can adapt for your distro:

• Install libsecret-1-dev: sudo apt-get install libsecret-1-dev
• Add a udev rule to give your user access to connected Fitbit devices, by creating a file at /etc/udev/rules.d/99-fitbit-sdk.rules with the following content: SUBSYSTEM=="usb", ATTRS{idVendor}=="2687", ATTRS{idProduct}=="fd13", GROUP="plugdev", TAG+="uaccess"
• Once you've added the rule, unplug any Fitbit devices and plug them in again for the changes to apply

... and I can't find the directory udev. I'm in /etc/ , but udev isn't there. When I run ls, I find

/etc $ ls
ODBCDataSources         debian_version  hostname       lynx            profile      ssh
PackageKit              default         hosts          machine-id      profile.d    ssl
X11                     deluser.conf    hosts.allow    magic           protocols    subgid
adduser.conf            dhcp            hosts.deny     magic.mime      python3      subgid-
alternatives            docker          init.d         mailcap         python3.8    subuid
apache2                 dpkg            inputrc        mailcap.order   rc0.d        subuid-
apparmor.d              e2scrub.conf    iproute2       manpath.config  rc1.d        sudoers
apt                     emacs           issue          mime.types      rc2.d        sudoers.d
bash.bashrc             environment     issue.net      mke2fs.conf     rc3.d        sysctl.conf
bash_completion         ethertypes      kernel         modules-load.d  rc4.d        sysctl.d
bash_completion.d       fish            ld.so.cache    mtab            rc5.d        systemd
bindresvport.blacklist  fonts           ld.so.conf     mysql           rc6.d        terminfo
binfmt.d                fstab           ld.so.conf.d   nanorc          rcS.d        timezone
ca-certificates         gai.conf        ldap           networks        resolv.conf  tmpfiles.d
ca-certificates.conf    gdb             legal          nsswitch.conf   rmt          ucf.conf
calendar                gitconfig       libaudit.conf  odbc.ini        rpc          ufw
cloud                   groff           lighttpd       opt             rvmrc        update-motd.d
cron.d                  group           locale.alias   os-release      security     vim
cron.daily              group-          locale.gen     pam.conf        selinux      wgetrc
cron.weekly             gshadow         localtime      pam.d           services     xattr.conf
csh.login               gshadow-        logcheck       passwd          shadow       xdg
dbus-1                  gss             login.defs     passwd-         shadow-      zsh
dconf                   gtk-3.0         logrotate.d    perl            shells
debconf.conf            host.conf       lsb-release    polkit-1        skel